cleanup toplevel namespace
Add basic top-level shortcuts
use "import scrapy" in templates
DOC use top-level shortcuts in docs
suggest scrapy.Selector in deprecation warnings
TST fix tests that became broken after adding top-level imports and switching to py.test.

py.test replaces AssertionError exception with its own subclass in an import hook.
For some reason when top-level shortcuts were added "except AssertionError" in
contracts.__init__ meant "except py.test AssertionError" while scrapy.exceptions.ContractFail
was still a subclass of a builtin AssertionError, so Contracts reported errors
instead of failures and this made tests in test_contracts.py fail.

For now - just disable fancy py.test asserts.
Support case-insensitive domains in url_is_from_any_domain()
Merge pull request #693 from redapple/domain-casesensitivity

Support case-insensitive domains in url_is_from_any_domain()
Merge top-level-shortcuts
response.selector, response.xpath(), response.css() and response.re()
remove .re() shortcut
update docs
update spider templates
Remove "sel" shortcut from scrapy shell$

Use response.xpath(), response.css() or response.selector instead.
document shortcuts in TextResponse class
Ammend example nesting selectors
Restore and deprecate "sel" shortcut
Merge pull request #690 from dangra/kmike-response-selectors

Added docs response selector shortcuts
Fix PEP8 warnings in project template files
Fix PEP8 warnings in spider templates