* Added TIN validation for Austrian numbers
* Added source of validation algorithms to header

* Refactored TIN unit tests to support more locales
* Added unit tests for de-AT TINs
* Added comments to isTaxID.js to explain behaviour of deAtCheck(tin)

* Added TIN validation for Greek numbers
* Added relevant tests

* Added TIN validation for UK numbers
* Added relevant tests

* Certain EU TINs might be entered with special characters which
should not affect their validity/be omitted according to the
specification. Such TINs are now sanitized before running checks
in isTaxID(str, locale).
* Removed en-GB validity check function (not needed, case already
covered in isTaxID(str, locale).
* Updated/simplified structure of regexes
* Updated de-AT tests as some previously invalid TINs are now
considered valid in line with the specification.

* Added TIN validation for Belgian numbers
* Added relevant tests
* Added local TIN names and validation scope
(person/entity) to comments

* Countries with more than one locale should now have only one
entry in the taxIdFormat and taxIdCheck objects, all others added
as aliases below the objects. This should help avoid repetition.
* Refactored nl-BE as alias to fr-BE
* Renamed frNlBeCheck to frNlCheck to reflect changes.

* Added validation for French TINs
* Added relevant tests

* Added validation for Cypriot TINs
* Added relevant tests
* Added tests for previously uncovered cases (calling isTaxID
without a locale, frBeCheck invalid checksum)

* Added validation for Hungarian TINs
* Added relevant tests
* Refactored return statements to be
one-liners where possible

Different locales might have specific needs wrt acceptable symbols
in TINs- in some all are omitted during validation, while others
only allow to skip a subset.

A new object `sanitizeRegexes` has replaced the previous array, where
locale-specific skippable symbol classes are to be placed. When all
symbols can be omitted the new variable `allsymbols` is referenced.

Aliases have also been added for the new object in line with the
others and the isTaxID function checks for the locale's inclusion in
`sanitizeRegexes`.

* Add TIN validation for German numbers
* Add relevant tests

* Moved de-DE check digit calculation routine
to new function `iso7064Check()` to be used
for other conforming locales.
* Add TIN validation for Croatian numbers
* Add relevant tests
* Refactor deDeCheck() to use iso7064Check()

* Add TIN validation for Bulgarian numbers
* Add relevant tests

* Add TIN validation for Czech numbers
* Add relevant tests

* Add validation for first digit of Greek TINs
* Refactor el-GR tests
* Add info for testable en-GB TINs

* Add TIN validation for Slovakian numbers
* Add relevant tests

* Add TIN validation for Danish numbers
* Add relevant tests

* Add TIN validation for Estonian numbers
* Add relevant tests

* Add TIN validation for Lithuanian numbers (as alias of et-EE)
* Add relevant tests

* Add TIN validation for Finnish numbers
* Add relevant tests

* Add TIN validation for Italian numbers
* Add relevant tests

* Add TIN validation for Irish numbers
* Add relevant tests

* Add TIN validation for Latvian numbers
* Add relevant tests

* Remove parseInt() calls in year extraction procedures of functions
to improve performance and readability

* Add luhnCheck() to be used by conforming locale TINs
* Refactor deAtCheck() to use luhnCheck()

* Add reverseMultiplyAndSum() to support new locale check functions

* Add TIN validation for Swedish numbers
* Add relevant tests

* Add TIN validation for Dutch numbers
* Add relevant tests
* Refactor enIeCheck() to use reverseMultiplyAndSum()

* Add TIN validation for Portugese numbers
* Add relevant tests

* Add TIN validation for Slovenian numbers
* Add relevant tests

* Add TIN validation for Spanish numbers
* Add relevant tests

* Add TIN validation for Romanian numbers
* Add relevant tests

* Add TIN validation for Maltese numbers
* Add relevant tests

* Add TIN validation for Polish numbers
* Add relevant tests

* Add support for both uppercase and lowercase letters
where not specifically defined in the DG TAXUD document

* Add verhoeffCheck() to be used by future locale TINs

* Add TIN validation for Luxembourgish numbers
* Add relevant tests

* Add supported locale list and info message to isTaxID() description

* Remove codice catastale validation subroutine from it-IT
(to be included in another upstream PR) for further review.

* General-purpose validation algorithms have benn moved
to `src/lib/util/algoritms.js` to support further use.
* Validation algorithms have been refactored to use strings
as input
* isTaxID has been refactored to use `algorithms.js`