Update PlistDocument.cs

Bugfix: Reading a dict in a plist document only handles every second key.
Update PlistDocument.cs

Bugfix: Reading a dict in a plist document without whitespace between tags only handles every second key.
Update PlistDocument.cs

Bugfix: Reading a dict in a plist document without whitespace between tags only handles every second key.
Merge pull request #83 from omd/patch-1

Fix to PlistDocument.cs ignoring every second key when reading a dict (from non-whitespaced plist files)