Added three new commands for saving arbritrary code and data to SDCard:
- Asset_StartExternal - Starts a block of code or data to be saved to the SDCard for later loading
- Asset_EndExternal - Ends the last block defined with Asset_StartExternal
- Asset_LoadFromExternal - Loads an external asset file into the address provided (including attic ram)
Use StartExternal and EndExternal to wrap code/data you wish to save to SDCard for loading via LoadFromExternal. If saving code be sure to use .pseudopc directive so that the code is assembled as if in the address specified.