standalone refactor
can append cache vars
something works
libagents now installs correctly.  need to fix tests
updated test input files
updated use cyclus to support tests
adds a base class for mixin or composed classes managed by agents
some minor cleanup issues
Merge branch 'gidden-mixin' into develop
Merge pull request #874 from scopatz/libagents

Libagents
moved test dir
adds a libagenttests and a cyclus_agent_unit_tests binary
added cyclus_stub_unit_tests binary
updated find cyclus to match cycamore
CMake -> cmake
currently builds agent tests