Tweak trampoling and support code to run gc-integration tests on amsjs
Fix some gc refing and unrefing issues.
Tweak details of calling into realloc_frame()
Refactor compilation to treat basic blocks individually.
Get basic tests running with refactored asmjs assembler.
Make for proper rpython
Get all gc_integration tests passing with asmjs backend.
Skip some failing tests with emscripten on 64bit host
Implement support for FORCE_SPILL instruction
Fix incorrect semantics of int_neg and int_invert
Fix incomplete semantics of INT_IS_TRUE
Make string operations deal with unsigned bytes.
Fix mis-matched semantics of int_mod.
Improve impementation of INT_MOD.
Simply some code-generation dealing with the frame
Fix parsing of js function calls with zero arguments
Fix incorrect callsig strings for float argument types.

It should be "d" rather than "f".
Add runner tests to the asmjs testsuite.

Many pass, some fail, needs more work...
Add ability to emit simple assertions in generated asmjs
Fix semantics of RAW_LOAD and RAW_STORE