Change licensing of patch sets

Instead of releasing into the public domain, release
under the license of the respective upstream project.
implement del x[idx], x[start, end, step]
add the python test file for del statement
fix the ic enable macro of delitem

make the implementation of del statement exception-aware
Need to filter out the LICENSE file in this tool
Get rid of destructors because they're not even getting called.

Will add them back later
Some minor improvements
add a try-catch around the repl
Clean up attribute lookups and add simple 'member' descriptors
Rename benchmarks->millibenchmarks

Not quite as small as microbenchmarks, which primarily
test just a single feature, but not full benchmarks either.
Add some a new test (a gcj solution) and start making it work
Fix a bug in expression evaluation order

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.
This was a cfg-construction bug
Start working on that gcj test

Added some string functions and fixed a couple bugs.
Improve the speed of some static analyses

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.
Implement ord() and string iteration
Implement set.__len__, dict.pop
Implement list.remove
run clang-format
Implement sum() and dict.get
Implement str.count
implement list.reverse()