Track loops sorrounding assembly
Add expression splitting
Check that the vectorizer has been correctly initialized
Create directory for code dumps if it does not exist
Fix dumping generated code for device backends
Make symbol rank optional.
Support -=, --, *=, /=, and implict casting to Symbol
None is not iterable
Fix cases in which children were not nodes.
working FunCall
Make semicolon handling for incr and decr consistent.

I am not convinced this is the Right Thing. It comes down to the statement/expression duality in C.
Make For a bit smarter about its payload
++a not a++, space around operators, handle = 0 correctly.
Documentation fixes
assorted grammar/typo fixes
Merge pull request #343 from OP2/remove-cgen

Cleanup and extension of PyOP2 AST.

- Adds -=, *=, /= and ?:
- Simplifies user syntax (strings, numbers cast to symbols).
Merge pull request #345 from OP2/doc-typos

Typo fixes.
Merge pull request #329 from OP2/pyop2-ir-expr-split

Split expressions if they are "large" to reduce register pressure.
Add top and bottom facet integration for zero forms.
Remove iteration set flags and add iteration descriptors

Add the iteration descriptor to the loop cache key.