System friendly *all* the things!

What's in this branch:

Removed hardware-banging startup code; use graphics.library and intuition.library to open a custom screen and install a custom VBlank server.
Multitasking now working, can load from floppy on KS1.3 and coexist with the OS nicely.
New system-friendly input for keyboard using input.device.
New joystick/CD32 pad support, done in a system-friendly way using potgo.resource.
New system-friendly CIA timer; tries to allocate either CIA B timer A or B using ciab.resource and installs an interrupt handler.
Removed all the ASM includes and pointed the Makefile at NDK-provided includes.
Moved C sources and headers into src and includes respectively.
New Makefile which is more maintainable, can compile with GCC or VBCC, and has a DEBUG mode as well as an optimised mode (default).
Added setup guide for GCC on Windows.

djh0ffman / PT1210