Sort out LDFLAGS/LIBS

This fixes compilation with Cantera on Linux for me.  It needs to be
tested on OSX before being committed just in case I regressed
something there.
Merge pull request #3 from grinsfem/linux_build_fixes

Sort out LDFLAGS/LIBS
Updated README to mention Google Group lists.
More fixes for unused variables warnings
Fix warnings in manufactured tests
Merge pull request #5 from grinsfem/warning_fixes_2

More warning fixes
Merge branch 'master' of https://github.com/grinsfem/grins into magentostatics