When specifying a const reference member variable in the constructor's initialization list, the argument must also be a const reference.
Make compilers happy by adding in a proper return instruction to the pycallback_object fall-through converter, even though it will never actually be issued.
Use LOG4CPP directories, not the library itself.
Fix abs block to work no matter the input type; addresses issue #660.
Merge remote-tracking branch 'michaelld/fix_clang_warnings' into maint
Merge remote-tracking branch 'michaelld/fix_abs_XX' into maint
Revert "When specifying a const reference member variable in the constructor's initialization list, the argument must also be a const reference."

This reverts commit d822103336b17d40f5e93ab441e3cbf5ad000ee0.