Fix loopjitting
- improve loop arg/ret discovery
Fix and test usecase for conditionally defined variable inside the loop
and other cleanups and more docs
Disable multiprocess testing for cuda testsuite
Add cuda context sharing among threads
Docstring
Cleanup
Allow GPU array to have zero size
DUMP_ASSEMBLY should trigger ptx dump
Dump assembly for ufuncs and gufuncs

Assembly code is dumped for @jit functions depending on the value
of config.DUMP_ASSEMBLY. This commit adds dumping of assembly code
for @vectorize and @guvectorize functions.
Merge pull request #864 from gmarkall/ufunc_dump_assembly

Dump assembly for ufuncs and gufuncs
Merge pull request #862 from sklam/fix_cuda_2

Fix cuda 2
Merge pull request #859 from sklam/fix_loopjitting

Fix loopjitting