generator optimizations

Adds a few C API paths plus sets tp_iternext and tpp_hasnext

Fix extra nonzero call for chained comparisons #1190

long: dealloc gmp memory

Replace None with Py_None and some other fixing.

Pyston already has Py_IgnoreEnvironmentFlag, just add it to sys.flags.

When try to support tk. The Py_None is a wrapper of pyston `None`. It
will conflict with other library's None. So rename the pure pyston
`None` to pyston_None. And use Py_None instead pyston_None when
possible. Just like dropbox#1231 for Py_True and Py_False

add _bisect, always_use_version support CAPI, set some frequent accessed slots

+ fix a leak in PyList_Insert

implement tp_str and tp_repr for more of our builtin types

Have function.func_globals always be dict-like

Internally we store it as either-dict-or-module, but when we expose
it to Python it needs to be given back as a mapping.  I looked briefly
into switching the internal representation, but that seemed like a much
more invasive change.

Also, add a pytest test that exposed this issue.

Add sq_slots & mp_slots to instance (issue #1197)

str: use cpythons [r]partition

it support non str separators
fixes #1297

Bump version numbers

docker: we are now using cython 0.24 + update readme for 0.5.1 release

str does not have `__iter__`

which hits an external server

use r12, r15 and rbx in bjit and inside bjit ICs, remove some nonzero checks

when possible

bjit: use a bitset for register tracking in the rewriter and use r12, r15, rbx, rbp in PPs and the bjit
Keeping the available registers in a bitset makes it more memory efficient and
also easier and more performant to calculate a subset of the registers.
I will soon implement the 'otherThan' functionality using it which would fix the current problem of only allowing to exclude one register