Good for a 10-15% speedup

I still feel like we can do much better here though

(Committed by kmod)
Closes #93

Make check_format actually useful

Add sudo for zsh installation

Property

Some small changes to simplify the generated IR.

Also make a note that the CPython development headers are necessary
for running the tests.

Fix typo in IOError format string

This fixes an annoying typo introduced in cfe83db0.

+ mark the alloc routines as no alias (=attribute(malloc)).
  This marks every alloc call as noalias in the IR.
  (While I felt somewhat frightened by the malloc attribute AFAIK the generated IR looks reasonable.)
+ inline the trivial Box constructor
+ fix dead allocs pass: we will now remove the useless list creation inside f2 in speculation_test.py

Small improvements for file objects.

The code was already in but it was turned off due to the
compile time regressions.  The addition af kill flags seems
to have fixed it.

We now have the locals() method working and can start to implement
other similar features.