Bump html5lib-tests submodule.
Add OS X Framework target.

- Share tests between iOS and OS X.
- Add prefix header for tests that includes XCTest.
- Extract HTML5LIBTESTPATH #define to Tests.xcconfig file.
- Framework deployable to 10.7 as that's the first version with full ARC
  support.
Formatting and comment fixes.
Unroll insertion mode-token type dispatcher.

Was super slow. Useful during development, not so much now.
Speed up tokenizing character entities.

- Binary search the win1252 replacement table.
- Only search part of the named reference table for the longest prefix match.
- Entity Fetcher utility downloads and formats the latest entity list from
  WHATWG.
Stop copying childNodes just to count them.

Bad for performance.
Mention OSX in tidied README.

- Mention Foundation.
- Fix sample code.
- Mention dependencies and deployment versions.