Added save_world()
Merge origin/master
Fix a bug in pinfo for index 20.
Fixed an issue where binds were linking too early.

Custom linking can now be provided per function, though
at this time, only bind and compile_error takes advantage of this. The link function
works much like optimizeDynamic, except it is called after function
resolution, so a function that is removed from the AST after optimization
may never be linked. compile_error helps to demonstrate this especially, and
can be used as a preprocessor error mechanism, to halt compilation if compiler
environment values are incorrect. This works much like C++'s #error preprocessor
directive.
Removed pinfo()[20] for the time being.
Added the possibility to change the list of online players in the server_ping event.