Fix constness of the set -> bool conversion
Add set pretty-printer
Add support from the count method from str

As a consequence, dispatch it as it is shared by the list class.
Add support for isalpha and isdigit methods from str
Harmonize comments on dispatched methods
Fix handling of Mod, Pow and FloorDiv update operator

They are not implemented the same as regular update operators.
Do not move Top-Level Class definition into main

Otherwise the SyntaxChecker detects an unknown attribute where
unsupported user classes is much more clear.
Support array concatenation through plus operator
String iterator can return char instead of char&

Python string are immutable.
Support reverse iteration on strings
Handle dummy case of an empty set temporarily updated

This result in a call to the update method from the empty_set, which is
pretty useless.

As a side effect, fix a few test case that were badly designed.
Merge pull request #234 from serge-sans-paille/small-fixes

Small fixes
More info in DEVGUIDE
Merge pull request #241 from serge-sans-paille/improve-devguide

More info in DEVGUIDE
Support using Python types as numpy dtype

To do so, the version of int() long() float() etc. without parameters
must be available.
Distinguish containers with dynamic size from containers with static size

Use a type trait to achieve this goal, useful for list to tuple versus
array to tuple conversion.
Support the len_of trait for itertools.imap

In the way, fix a very subtle way of iterators not iterating on the same
object due to copies...
Support passing a tuple as parameter of numpy.ndindex

Also fix a bad iterator typing issue in the associated iterator.
Fix behavior of the modulo operator in presence of negative input

C++ and Python differ on that point: the output is always positive with
Python and not in C++.
Support augmented assign for ndarrays