Go language support

Hello,

there had been some Go support for NB 7, which had been incomplete (due 
to comments), and I don't have the source code for it.

Now I've started a new implementation from Golang.g4 grammar found in 
the antlr4 repositories.

The grammar file is under BSD license, so that should not cause 
problems. My only modification has been to remove the "-> skip" directives.

As an implementation guide I basically used 
http://wiki.netbeans.org/Netbeans_Rcp_Antlr_Integration_Index, but I had 
already to add some LanguageRegistration to get highlighting working.

Currently I'm working on the formatting part. Now I have to use the 
parser, and now I'm getting a conflict with the LanguageRegistration, as 
CSL ParserResult is expected instead of Parsing API Parser.Result.

Could someone probably help me to fix this? Source code is at 
https://github.com/OldGrumble/go-language-support-proto.

Kind regards
Peter