TestFlight 1.2 + Few extra features

Latest version of TestFlightPlugin doesn't work with Plugman (which apparently now requires specifying full path for source files), so you should at least apply the last patch.

Additionally, I upgraded to TestFlight SDK 1.2 and added two features:
- a method to set the real UUID (https://github.com/j3k0/TestFlightPlugin/commit/e0ef571284acd005eb13337885808c3e42155eb2 and https://github.com/j3k0/TestFlightPlugin/commit/213deeb6e0665db2aa497a246e36644afd285f72)
- support for TFLog (https://github.com/j3k0/TestFlightPlugin/commit/10e6cb6c2cca1ae6e41d1487cee2e6851837183f)