Implement anonymous struct tuple type.

Syntax is (type1, type2, ...).
Test and note for tuple types.
CTuple indexing support.
CTuple type unpacking.
Remove redundant lhs analysis.
CTuple type inference, unpacking.
Generalize assignment unrolling.
Constant array slice size check.
Assignment to array slice now works.
CTuple arithmetic.

Fall back to Python conversion for now.
Various test fixes.
More type name mangling.
Better type identifier creation.
Add empty declaration code method.
Fix bug exposed by specialization and declaration code caching.
Merge branch 'master' into ctuple

Conflicts:
	CHANGES.rst
Use type identifier in a couple more places.
Merge branch 'master' into ctuple

Conflicts:
	Cython/Compiler/PyrexTypes.py
	Cython/Utility/TypeConversion.c
	tests/run/arrayassign.pyx
Fix test (discovered) broken in merge.
Fix tuple array assignment test.