Typewriter, multiple builds

I want to separate this plugin into two builds, one for ST2 and one for ST3. I am not planning to continue development of the ST2 build; it will be moved to its own branch (st2). I've been using the tags versioning method, which I would like to retain for ST 3 branch, which I will relocate to master (it's in the devel branch currently).

Give the above, does this PR make sense?