Untested parser based on generic URI syntax.
Test/fix new URI parser; change Codecs#percentDecode to pass nulls
Give up on pluggable path parsing for now. Just stick to text paths.

- Delete everything to do with path segments as text + params
- Add general relative path processer
- Minimal encoding of path segments
Add a couple path tests; rename (and use!) isAbsolute{Reference}
Use ClojureHelper.init on each class that uses it
No more generic percent-encoding (all based on spec now)
Merge branch 'uri-parser'
Merge branch 'spec-encode'
Merge branch 'path-simple'

Conflicts:
	src/main/java/com/brightcove/johnny/Constants.java
	src/main/java/com/brightcove/johnny/http/Codecs.java