Improvements to HTTP parsing
Structured Overlay support:
* Add Peer Protocol detector
* Add RIPPLE_SINGLE_IO_SERVICE_THREAD setting
* Preliminary HTTP header parsing logic (disabled)
Update ripple-lib integration tests
New integration tests:
* New tests for autobridging and freeze
* Discrepancy detection tests
* Don't let Mocha suppress load time errors
In JSON, output unprintable currency codes as hex
Fix a case where we put an extra node in the SHAMapDiff
Add new memo restrictions