Use company-ghc--in-comment-p instead of syntax-ppss
Add unit test for qualified keyword candidates

"Given these imported modules" now takes table of module and alias.
Implement completion for qualified keyword

Assgin candidate type and optional information to
company-ghc--prefix-attr in prefix command, so that it can be used in
subsequent commands, such as candidates.
Merge branch 'master' into qualified-completion
Merge branch 'master' into qualified-completion
Use 2 dashes for some internal variables and functions
Handle the case multiple modules have one alias
Make meta info work for qualified imported keywords
Return cons for qualified imported keywords

So that completion begins when dot is entered.
Reset company-ghc--prefix-attr in candidates
Document completion for qualified imported keywords
Merge branch 'qualified-completion'
Bump version to v0.1.0