Basic test for sceKernelReferThreadStatus().

Needs more investigation.
Add schedf() and checkpoint() to common.

Use them everywhere, so might as well.

Most things should still compile since they use inline, I think.
Make the create test a bit prettier looking.
Add a test for sceKernelStartThread().
Test additional arg length/ptrs in start thread.
Test the stack layout after creation.
Merge pull request #71 from unknownbrackets/thread-funcs

Some tests for basic thread funcs