Allow comments in hash lines.

Fixes #52
Allow non-hash comment lines in hash blocks.
Spaces aren't needed after a comment.
Tweak comment parsing. Bump version to 1.4.

* Allow # within hashes. (After the first occurrence of whitespace, you are no longer within a hash. Think of peep hash lines as a language that supports bare words as an equivalent to Python's quoted strings: quoted strings can contain #.)
* Require a space after the colon that follows the hash type, and require one between the # and the hash type. We did before, and I don't see a reason to loosen this up atm, since we can never re-tighten it.
* Don't bother explicitly stripping the space before a comment, since we don't do anything with comments anyway.
* Count comment lines that start with whitespace as contiguous peep comment lines for the purpose of hashes_above(). (pip allows comment lines to have leading space.)
Merge support for partial-line comments on hash lines. Close #52 and #54.