Easy manipulations of non-SI quantities

[ma-laforge]

Hi SIUnits users,

I find the SI units module very impressive.

Often though, I find I do not need a tool that tracks units, as much as I need something that can better deal with unit conversions. I also find it can be a hassle to write algorithms using the "canonical" form: base SI quantities. This is especially true if one wants to write programs with imperial units.

*NOTE: I also noticed Tim Holy initially dealt with more of the non-SI quantities in his original "Units" module (includes Inch, Foot, Yard, ...):
https://github.com/timholy/Units.jl/blob/master/src/Units.jl

In my own attempt to deal with this issue, I built a test module that works with arbitrary units. It seems to complement the SIUnits module very well:
https://github.com/ma-laforge/testcases/tree/master/units_test (see: units_test.jl)

Hilights:
-Performs "automatic" unit conversion, if needed.
-Does not intrinsically need a canonical form (ex: Distances do not all have to be stored in meters).
-Requires relatively little overhead on the programming side.
-Collaborates with (depends on) SIUnits if unit tracking becomes necessary.

Questions:
-Would the SIUnits module not benefit by integrating this functionality?