Integrate all information from TechTreeImproved into the existing class
TechTree. Thus TechTreeImproved is deprecated and removed from the
Python-API.

CCUpgrade (sc2::UPGRADE_ID) does not contribute much and makes code
more difficult. Especially in Python, since it does not convert between
types implicitly.

This is a nice feature, but it took too long to force CMAKE into
outputting the binary into the correct directory.