No documentation on how to create or edit content

[kavika13]

Add tutorials to wiki for:

• High level: What the different content types are and how they are used
• Editing an existing level
• Adding new behavior to an existing level
• Basic level creation
• How to customize the music for a level
• How to customize sounds for a level (?)
• How to load existing content into a level (?)
• How to compile a level
• How to add a level to a level playlist (one of the difficulty-level .jmg scripts)
• How to create 2D graphics and animation
• How to compile a 2D graphic/animation into a mesh
• How to use a new mesh in a level
• The supported API exposed to scripts
• How memory is shared between scripts and the Jumpman Zero engine
• How to add new APIs to the Jumpman Zero engine for scripts to use

... plenty more. This should probably get split out into sub-issues.