Travis: Update gcc only if its the current compiler. Add updateing clang to newer version if its the current compiler.
Travis: Update gcc only if its the current compiler. Add updateing clang to newer version if its the current compiler.

realXtend/tundra-urho3d,realXtend/tundra-urho3d,realXtend/tundra-urho3d,realXtend/tundra-urho3d,realXtend/tundra-urho3d