Added some details on hosting on IIS and OWIN
Unit Tests: tweaked FdbTest base class
Added WithReadYourWritesDisable() and WithReadAheadDisable() transaction option helpers, fixed WithNextWriteNoWriteConflictRange() to require a writeable transaction type
Fixed invalid state checks for GetReadVersionAsync() and SetReadVersion(..)

- these methods are allowed on read-only transactions
- it is legal to call GetReadVersionAsync() after CommitAsync()
Slice: added a few BigEndian and 16-bit helper methods
Added a ToString() on the various SafeHandles, and added a #if CAPTURE_STACKTRACE to help troubleshoot transaction and db object leaks
Tuples: UnpackLastWithoutPrefix(...) displays the key and expected prefix in the error message

- helps troubleshooting problems with key selectors
- only in Debug builds for now
AsyncLinq: added various SumAsync(...) LINQ methods that can be used to add together the values of a range read

- Useful for layers that need to count or rank things
Removed unused variables