logging: now with awesome color and fine-tunable verbosity levels

see `pfasst::log::test_logging_levels()` for usage examples
Merge pull request #126 from torbjoernk/feature/fix-cmake

fixing #124 and some improvements to 3rdparty configuration
adding .mailmap file to fix up commit authors
Merge pull request #128 from torbjoernk/feature/add-mailmap

adding .mailmap file to fix up commit authors
Merge pull request #123 from torbjoernk/feature/more-awesome-logging

logging: now with awesome color and fine-tunable verbosity levels
cmake: fix bug #130