Added types to #have_func calls
Fixes two "unused variable" inclusion warnings

lib/nmatrix/nmatrix.rb:566:
warning: assigned but unused variable - new_cap

lib/nmatrix/lapack.rb:196:
warning: assigned but unused variable - result
Reverted a few extconf changes
Removed another inclusion warning
Fixed problems with extconf default library paths
Added args to have_func calls
Merge pull request #238 from andrewcsmith/fixing_warnings

Fixed issues with the #have_func calls and the "unused variable" warnings