Set default tab width to 2 for vi editor only for these two files.
Only give warning for 'bad' MinGW compiler when no SSE option given.
So that user does not receive the same warning subsequently after taking action to set the URHO3D_SSE option explicitly or after the correct setting has been set by the script.
For Travis CI - upload snapshot source packages to FRS.
Test [ci package].
For Travis CI - switch CI build to use OS X build environment.