In VIM, you can force a file type by writing a model like this
# vim:syntax=html filetype=html
I wanted to get the same for Sublime Text. For example, I liked Sublime Text 2 for using MarkDown syntax for some file with the extension .txt.
There is a Modelines plugin for Sublime Text: https://github.com/SublimeText/Modelines
To do this for each file with a specific extension, with an open file, go to the View , Syntax , Open all with current extension as... menu and specify your preferences there.
View
Syntax
Open all with current extension as...
It doesn't seem possible to install it on a file or project, but maybe you should take a look at this package: https://github.com/phillipkoebbe/DetectSyntax
Another package management tool available for ST2 / 3 is https://github.com/kvs/STEmacsModelines
using it is very simple, from the docs:
Somewhere in the first five lines of the file, add a line corresponding to the following:
-*- key: value; key2: value2 -*-
or
-*- syntax -*-