Fixed problems reported by GCC with MRPT_WARNINGS_ARE_ERRORS=ON
Fixed some problems reported by CLANG with MRPT_WARNINGS_ARE_ERRORS=ON
Fixed more warnings reported by clang compiler
Merge remote-tracking branch 'upstream/master' into CleaningWarnings
Fixed more warnings reported by clang compiler
std::abs is defined in the header cmath
Merge pull request #68 from piponazo/CleaningWarnings

Cleaning warnings