Changes to Popcorn by Rik Griffin:

Removed all the DeskLib stuff, so it compiles using Acorn Cv5.
People compiling this version of Popcorn with DeskLib should define
DESKLIB before compilation.

Added loop feature for Resources file, using a pseudo-group called !!!!.

Changed timer value to a signed short int. (a real bug in the original)

Added plot offset, and made the std_plot flag and the Popcorn_Outside
function (used for the attn_...out and kill_...out flags) understand it.

Tried to compile with Dr Smith's MemCheck, but it caused a compiler error :(

Added Popcorn_PlotSpriteNoBounds, doesn't check either the plot window
or the screen bounds. If the sprite gets plotted outside the screen
memory, bad things will happen. So be careful.

Added in a couple of changes from Mr Bloch's Popcorn 0.01.
Nothing major though.

Changed the assembler routines a bit to make them more APCS compliant.
In particular, made sure status flags are preserved over function calls
(by using MOVS pc,lr or LDMFD sp!,{pc}^), and removed the storing of
r0-r3 at start as it's not needed.

Created a new type of popcorn object, specially simplified to allow
extra optimisation, called "dust", along with corresponding
Popcorn_ProcessDust and _NewDustTable, _NewDustObject,
_NewDustPrototype, _DustOutside, _DeleteDust. Also Popcorn_PlotPoint,
which plots a single dot.

Dust object tables are not searched for free slots when a new object is
to be created. Instead the table is only used linearly, and if
_CreateObject is called with a flag set, the oldest object in the table
will be overwritten with the new one, if the space is needed.

Added new routine Popcorn_NewSubTable. This takes a table pointer and
the size of the user_data struct for that table. It then reserves space
for all the user_data for that table and sets up the user_data pointers
for each object.
Removed "obj->user_data=NULL;" from Popcorn_NewPrototype. Because it
would not work with _NewSubTable.

Added experimental sparkly dust.
Removed sparkly dust, cos it was pants.

Reworked Popcorn_Process and Popcorn_ProcessDust to avoid the compiler
fault that appears when -zpc1 -g flags are used.

Another couple of changes to dust: timer decrement has been removed, it
is always 1. Added colour_div, to allow colours to be changed less often
than every timer decrement cycle.

Compiled Hive v0.01 with new Popcorn.
