Parse json with leading whitespace.

Leading whitespace in a json string for an empty object (e.g. " {}") is
only successfully parsed for user-defined classes - it fails in one way
or another for: Dictionary<string, string>, Dictionary<TKey, TValue>
(any other type of dictionary), Hashtable, JsonObject, or
KeyValuePair<TKey, TValue>. Furthermore, for a user-defined class, the
shortcutting check for an empty object is not invoked if there is any
leading whitespace.

Added index parameter for JsonTypeSerializer.IsEmptyMap. Most callers of
this method were already calculating the index if the first
non-whitespace character, but IsEmptyMap was not taking this index value
into account - it was returning false when it should have been returning
true.

NOTE: JSV is not affected by this change, only JSON.
Merge pull request #277 from bfriesen/leading_whitespace

Parse json with leading whitespace
Adds support for property name conventions on per-type JsConfig
Merge pull request #279 from roryf/master

Support property name conventions in per-type JsConfig<T>
INCR to v3.9.37
fixed double underscore issue
added unit test for double underscore issue
changed StaticParseMethod to not expect exception
unit tests for StaticParseMethod, reuse refactoring there
Merge pull request #282 from BrannonKing/master

removed expected and common exception
Adds supporting for WinRT. Fixes WindowsPhone sln.

NETFX_CORE stands for the #define flag for WinRT.
Fixes WindowsPhone build.
Caches assembly objects for WinRT
Update StructTest for MonoTouch/Xbox/Silverlight
Merge pull request #283 from abattery/master

Adds supporting for WinRT. Fixes WindowsPhone Build.
Refactored Win32 support to be DRY'er
Don't leak WinRT feelings
Inherit more platform cruft from SS.Common
more WinRT re-factorings
Fix WinRT build errors