Switch clang-format to C++11 mode

Looks like for now this only changes double-closing-angle-brackets
(now formats "> >" as ">>" in templates), but apparently it has
effects on raw string literals as well.
Reduce the default test threads from 4->1, and increase test time limit
Wip
add this
EnvironmentError.__str__
wow it works!
Convert Makefile targets to support self-hosting
Now it works for real
some list fixes
Change makefile rule to only rebuild ext_pyston when necessary
[HAX] not addressing these for now