Updated WADL-Tools to 1.0.21

This addresses an issue where extension attributes like rax:roles are
not handled correctly when the attributes are in an element with an
href.
Merge pull request #190 from RackerWilliams/wadl-tools-update

Updated WADL-Tools to 1.0.21
Fixed issue: rax:roles in method references were not handled correctly.

Copied method after normalization was keeping a reference to its
source. This is well and good, but the rax:roles transform changes the
copy, so assumtions that copy and source are identitcal were being
broken.

The fix, simply removes the reference to the source if rax:roles are
applicable.
Merge pull request #191 from RackerWilliams/rax-role-fix

Fixed issue: rax:roles in method references were not handled correctly.
Enable implicit conversions in core tests.
Merge pull request #192 from RackerWilliams/implicit

Enable implicit conversions in core tests
updated RELEASE.md file
revised RELEASE.md. No performance tests have been performed on preserveRequestBody feature yet
updated RELEASE.md with wadl-tools update, rax:roles at method level fix, and enabling implicit conversions in core tests