Detailed browse command

Browse command can show more info about declarations with -d flag.

Example of output for 'ghc-mod browse Data.Either -d':

    Left
    Right
    data Either a b
    either :: (a -> c) -> (b -> c) -> Either a b -> c
    lefts :: [Either a b] -> [a]
    partitionEithers :: [Either a b] -> ([a], [b])
    rights :: [Either a b] -> [b]

This pull request is important, because I am using this feature in SublimeHaskell plugin for SublimeText2