1.0.19 - sprite reloading and imrovements

Additions:

• Sprite reloading! Call sprite_set_live anytime and your sprite will be updated whenever you change it from GameMaker or via external software. 

Improvements:

• Specifying server URL as `undefined` will have GMLive not attempt to connect while still allowing to use it's other functions.
• Variable access and function calls now work on deactivated and destroyed instances, save for a few exotic use cases.
• Expanded documentation with more FAQ type topics.

Fixes:

• Fixed GMS2-specific `0x` (instead of `$`) hexadecimal prefix not working.
• Fixed GMS2-specific `return;` (instead of `exit`) syntax not working.