user visible: used for all non compiler generated names, name could be used in a single block or multiple
              all frames contain atleast this vregs in order to do frame introspection
cross block : used for compiler generated names which get used in several blocks or which have closure scope
single block: used by compiler created names which are only used in a single block.
              get reused for different names

we assign the lowest numbers to the user visible ones, followed by the cross block ones and finally the single block
ones. we do this because not all tiers use all of the vregs and it still makes it fast to switch between tiers.

major bjit improvements

float.cpp: now that we have float.c use some of the functions directly

this also workarounds the problem we were having on ubuntu 16.04 where we have to use std::isinf instead of isinf()

also add a option to pass MAP_32BIT to mmap

also fix a build error when ICs are disabled

Temporarily disable the clang build on travis-CI

Somehow this PR is taking longer to build, I assume from somehow missing
the build cache.

Assuming that it's a caching issue, bump up the time to satisfy un-cached builds.
If build times continue to increase we will run into this problem again (can only
regenerate the cache with a successful build but a successful build needs the cache),
but this will let us defer it a bit longer :)  Travis-CI builds are max 120 minutes.

Fix std::move error on temporary object

since we were installing it from the LLVM APT repo, which they
took down since it was getting too expensive.  I guess we can
just run with the gcc build until that situation gets resolved.

exec, input: if globals has no __builtins__ add it as a dictwrapper

update list of failing cpython tests

Bump version numbers

Some packaging / distributing updates

before we added a it as a module which made code fail
which does something like __builtins__["unicode"]

Switch to CPython's descrobject.c

The behavior changed in CPython 2.7.4, and Travis-CI runs 2.7.3.

until I realize that it's because we were passing more tests than we expected.

Create a simple Dockerfile

This is for adding a guard on a non-immortal object, since we need
to be safe against that object getting deallocated and a different object
is allocated in its spot.

We had support for this already, but it leaked memory.  The biggest was
that we never freed our runtimeICs, so if those ended up getting any GC
references in them, then we would leak memory.  So I started freeing those,
but then that exposed the issue that the ICInvalidators expect that their
dependent ICs never get freed.  So I added back a mapping from ICSlotInfo->
ICInvalidators that reference them.

via their descrobject.c