http: switch to regexp-less, LF-compatible js parser

See this[1] comment for more details and benchmark results.

Notable changes:
 * Removed all regexps. Only request URLs are not validated
currently.
 * Added globally configurable start line length limits
 * Chunk size parsing no longer line buffers
 * Lines can end in just LF too
 * Faster than the original regexp-based implementation

[1] nodejs#1457 (comment)