Merge pull request #3 from amjith/master

While statment
Performance improvements.
Document our use of %pure-parser
Add the gc module
Significantly reduce memory usage.
Increase chimp_int_str buffer
Make sure collection_count is properly initialized.
Add msg() type
Initial (broken) pass at task send/recv
Added ChimpMsgInternal
Implement the 'spawn' keyword.
Initial implementation of waitable tasks.

Communication between tasks not working correctly just yet.
Update the TODO list
Tweaks
Fixing stuff ...
More fiddling.
Major refactoring for tasks.
Dumb bug in chimp_array_new_with_capacity
Glaring bugs in msg.c
Message passing.