Support for right-to-left decomposition

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So far the package is written with left-to-right decomposition in mind. While it might work in other contexts, it would be best to explicitly support languages written from right to left in the decomposition algorithm.
Suffix search in particular could benefit from this enhancement, as well as unsupervised use of word lists to a lesser extent.

Things needed:

• add or modify corresponding languages by introducing a constant like REVERSE_ORDER
• add a parameter to relevant parts of lemmatization strategy

Probably after release of v1 as the package is still being actively worked on.