Add `cytoolz.utils.dev_skip_test` decorator to skip tests for dev versions.

These tests depend on `toolz`, and it is annoying when `toolz` changes in
the middle of a PR.  Now, the things these tests check for only need to be
updated before being uploaded to PyPI.
Move `dev_skip_test` into a module in "tests/" directory.

It was in `cytoolz.utils`, which added `nose` as a dependency.
Bump version to '0.6.2dev'
clean up some unnecessary C-API usages and integer sizes

note: integer size fixes which require corresponding changes in itertoolz.pxd
Merge pull request #26 from scoder/patch-1

clean up some unnecessary C-API usages and fix integer sizes
Add test for `dev_skip_test`
Add scoder to AUTHORS.md.  Welcome to CyToolz!
use cythonize() instead of old-style distutils hack
replace "int" usage by safer "Py_ssize_t" types to avoid unnecessary range limitations
Merge pull request #28 from scoder/cythonize

use cythonize() instead of old-style distutils hack
Merge pull request #29 from scoder/int_fixes

replace "int" usage by safer "Py_ssize_t" types
Merge pull request #27 from eriknw/authors_scoder

Add scoder to AUTHORS.md.  Welcome to CyToolz!
remove some unnecessary C-API usages
- list comprehensions are actually faster than repeated calls to PyList_Append()
- Py_XDECREF() works nicely on PyObject* (and the C compiler will usually drop the NULL check)
- isinstance(x, builtin) translates directly to a PyBuiltin_Check() call
Merge pull request #23 from eriknw/dev_skip_test

Add `cytoolz.utils.dev_skip_test` decorator to skip tests for dev versions
Merge pull request #30 from scoder/less_explicit_capi

remove more unnecessary C-API usages
add join

This is ugly and likely inefficient.  Help.
split out different joins into different classes

I'm not sure that this is worth it
single join class with single __next__
remove loose __iter__
add join to __init__.pxd