IRenderHandler Changes: Init Function

Created tweaks to the IRenderHandler interface to add init functions.  The primary purpose of this is to provide custom dimensions' SkyRenderers control over nighttime stars (as the stars are rendered once in the RenderGlobal constructor).  Because the init function was added to the interface, similar hooks were provided for the CloudRenderer and WeatherRenderer.  The SkyRenderer however is the only one that overwrites default behavior.

Note the first commit in this is an artifact of git.  The commit was rolled back but it's still in the history.
Note also that the line numbers may not match entirely.  There might have been an error with reverse patching the Forge sources and diffing the new modified versions.  If there's an issue let me know and I can analyze it more closely.