Allow cache module to be given in RGF constructor

[c42f]

This exposes the full constructor (without the need for specifying module tags), as we seem to need this for utility functions which want to cache the RGF in a user-specified module.

Looks like this is needed to make https://github.com/SciML/ModelingToolkit.jl/pull/769 less hacky.

[codecov[bot]]

Codecov Report

Merging #26 (f76395c) into master (076d6df) will increase coverage by 3.97%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #26      +/-   ##
==========================================
+ Coverage   89.36%   93.33%   +3.97%     
==========================================
  Files           1        1              
  Lines          47       45       -2     
==========================================
  Hits           42       42              
+ Misses          5        3       -2     

Impacted Files	Coverage Δ
src/RuntimeGeneratedFunctions.jl	93.33% <100.00%> (+3.97%)	:arrow_up:

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[ChrisRackauckas]

Should this get mentioned in the README? I think it should, and it should be the "final" piece of this library. Thanks @c42f for taking the difficult parts on!

[c42f]

the "final" piece of this library

25 could be nice I guess. But really it would be great if the compiler just supported callable methods more directly... this library is always going to be a hack :-)

[ChrisRackauckas]

A hack, but a useful one for at least the next year or two!

[c42f]

Right!