Look into compiling source to speed up load time

[molovo]

I've got two branches open currently to look into this:

• experimenting_with_compiling moves the core into a src folder, and adds a build script which concatenates the entire source into a single file, and then runs zcompile on it. It also compiles all executable scripts and autoloadable functions in packages when they are linked.
• experimenting_with_lazy_loading simply defers the loading of internal commands until they are called, rather than loading them on zulu init.

I would have expected both the above methods to have had some effect on startup time, but actually they both made it slower, which surprised me. If anyone has any ideas on how either of the above methods could be used to improve performance (or any other suggestions), please let me know.

[molovo]

Managed to get compilation working properly, so this will be included in #49.