Some pct encoding bugs
Make sure pct-decoding restarts immediately following an error
Be lenient when pct-decoding incorrectly pct-encoded strings.

That is: pct-decode incorrect encodings to their literal values rather than failing with cryptic substring errors or Scanf overconsumption
Clarify Uri.of_string documentation. Fixes #31.
Merge pull request #32 from dsheets/pct-bug

Be lenient when pct-decoding incorrectly pct-encoded strings