third-party/README.md: Add URL to my libRocket fork

This is the source tree used to build and package the library.
nomlib.sublime-project: Fix usage of SwitchScript pkg
Introduce <, <=, > and >= operator overloads

* VersionInfoTest.cpp: Add unit tests for the new operator overloads.
* version.hpp.in: Add include guards (prevent duplicate inclusion).
SpriteSheet: Re-add total # of frames metadata

* nomlib.json: Bump version up to v0.4.1
* nomlib.xml: Use the same version scheme used by nomlib.json.

* SpriteSheet: Use nom::VersionInfo struct for version storage.
* SpriteSheet: Validate min file spec ver of v0.4.0 for deserialization
and use (load) total_frames metadata only when ver > 0.4.0.
Rename nomlib.json && nomlib.xml && mv ../nomlib

This matches our local file and directory hierarchy for custom
TexturePacker exporters.