Handle GOPATH With Multiple Entries

[joefitzgerald]

https://code.google.com/p/go-wiki/wiki/GOPATH

Since the $GOPATH variable can be a list, the rest of this document will use $GOPATH to mean the first element unless otherwise specified.

• Use regexp to split GOPATH if required
• Provide array of GOPATH elements to components
• Use first element of GOPATH when replacing $GOPATH in Gofmt Path and Golint Path preferences