Regex bug, syntax highlight, settings loading and word_separator changes

Hi,

I've just made a few changes to Corona Editor.

1. I've fixed the regex error. [completions.py:48] the pattern wasn't being escaped, so if your prefix included a '(' you would get an error
2. Settings are now loaded using sublime.load_settings rather than checking view (seems safer)
3. The word_separators for the view are no longer modified - there was a bug where the code doesn't check whether the view is for a Lua file before modifying them, so the separators will be modified even when editing Python or Javascript. I experimented a little, and it seems to work fine as the ```find_completions``` function seems agnostic to the separators.
4. I've tweaked the syntax file. The little tweak seems to fix the local function keyword highlighting issue.

Also, this is the first time I've used GitHub to do a Pull Request, so let me know if there's better ways of doing this. Ideally I would have split the changes into smaller requests.

Tom