getSpecies was defined in two translation units. This was not an issue
for regular builds but broke unity builds. this has been refactored to a
single function in utils.h
also added ability to use Compositions as a std::hash in unordered_* types. Further added a constructor to build a Composition from a const CompositionAbstract&
Composition objects now must be built from vectors of molar abundances. Things such as mass fraction and number fraction are computed on the fly (with some caching for performance). This will allow for many fewer issues when converting from solver space to composition space.
BREAKING CHANGE: The entire old API has been broken. There is no longer any need to finalize. In fact the entire concept of finalization has been removed. Further, the entire CompositionEntry and GlobalComposition data structure has been removed. Any code written for the old version will no longer work and major reworking will be needed to use the new version.
The composition object is now a specialization of the abstract base CompositionAbstract. This interface enforces getters but not setters (those are left up to children). The intention here is that other code can specialize particular getters for cases where special handling (like unrestricted amounts of one species) are required.
