Updated Golang extension for Komodo.

1. Base the language service on LexCPP+backquotes, instead of UDL
2. Add preferences for golang/gocode/godef, and a GOPATH check
3. Fix a linter bug: squigglies weren't getting cleared when there were no errors in the buffer.
4. Linting is done with the gofmt tool, instead of invoking 'go build', which is more expensive.
5. Added a DTD file for chrome-side strings