Fix operators and add more scopes

Those weren't even valid at all in AutoIt.
Add detection of escaped quote within quotes and highlight send-keys only within strings
Remove unsupported number suffixes
Add .gitignore
Make it visible when a quotation mark at the end of the line is missing
Match underscore for concatenating multi-line expressions
Merge pull request #2 from FichteFoll/master

More Language Definition Enhancements. Closes Issue #1