Effectively rendering openfile.lua completely obsolete, which is why it
was deleted. filepicker.lua is now way smarter, handles file creation
and has a documentation file in LDoc.
Also replaced make build-doc with make build-doc-html so we can easily add new documentation formats in the future.
To add ctrµLua API autocompletion to Sublime Text, simply copy the output directory (doc/sublimetext) to your ST's package directory.
