Parse whitespace and comments

[S11001001]

As of 97ed3b2:

λ> :l Ermine.Console.Module
...
λ> testLoader "Prelude.DB"
Left (interactive):1:1: error: expected: module header

remove whitespace at top

λ> testLoader "Prelude.DB"
Left (interactive):1:1: error: expected: ":",
    "data", "infix", "infixl",
    "infixr", "postfix", "prefix",
    "type", end of input,
    term variable
-- foreign data DB a 
^                    

/cc @joshcough

[S11001001]

I believe this needs a new Trifecta release to fix completely, and thus #17 fixed as well. /cc @ekmett

[S11001001]

196d864 should deal with the first of these; thanks @ekmett for the tips.