Implementation of dict comprehension

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>

Implement list.index()

LivenessAnalysis: Cache BB liveness info to improve performance

Move some things to calling the *Internal methods,
which don't do patchpoint-checking, which wouldn't apply.

Reduce some unnecessary string-creation.

Also fix some of the things that it reported.

Have to patch the tool to make it work, since it wants
to use the CLANG_CXX environment variable to pass information around,
but the Pyston Makefile uses that variable as well.

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>

Brings down runtime of gcj_2014_1c_b.py from 2secs to 0.7

implement del x[idx], x[start, end, step]

implement list.reverse()

Before was using some bad iteration strategies for
fixed-point computation: LIFO for definedness analysis
(very bad), and FIFO for type analysis (bad).

Switch both of them to use a priority queue that picks the
block with the lowest index; this is an order of magnitude
better on the new gcj test but still is fairly slow.

Added some string functions and fixed a couple bugs.

Also, give up on maintaining 100% error message compatibility
with CPython.  There are some places where it's kind of silly
to do this since the messages seem based on internal implementation
details; namely, whether to output at the global scope:
NameError: global name 'x' is not defined
vs
NameError: name 'x' is not defined
This depends on whether any function has been defined that has
a "global x" declaration.

Instead, make the tester a little bit smarter to know that certain
classes of error messages should be treated as equivalent.

Not quite as small as microbenchmarks, which primarily
test just a single feature, but not full benchmarks either.

Will add them back later

add the python test file for del statement
fix the ic enable macro of delitem

make the implementation of del statement exception-aware

Instead of releasing into the public domain, release
under the license of the respective upstream project.

Updated exception handling in:
	src/runtime/types.cpp
	src/runtime/builtin_modules/builtins.cpp
	src/runtime/builtin_modules/math.cpp

Adds a non-optimal implementation of int.__divmod__ + tests

Change the logic to determine path to parse_ast.py, otherwise it breaks usage of pyston binary.