CMake: build anyoption as library

This way it is not compiled with the very strict compiler flags
used to compile opentxs code.
opentxs: fix -Wold-style-cast
Merge pull request #267 from toxeus/fixOldCasts

opentxs: fix -Wold-style-cast
CMake: Packaging: Add number of commits since last tag in version string (file name)