Seems that your highlighter cannot be installed via Package Control. It says cannot load Light Theme. Besides, Preferences → Package settings does not show an entry to edit your settings.
I gaveup Package Control and have to install manually create each file. It works but the autocompletion is somewhat worse than what it was in ST2 (in ST2, all variables & function name existed in currently editing .ahk are listed for autocompletion - this no longer works in ST3)
I havent given (cant give) ST3 a try . It's shareware .
Preferences -> Package Settings seems to be a new option . It isnt in ST2.
As for Package Control, I have submitted the package but the fact is that sentience, one who accepts the pull requests there hasnt been online for some 20 days and so my package stands there in the queue.
Last pull is #1247 and mine is #1254, so last time he gets online , I will have my thing accepted .