allow spider allowed_domains to be set/tuple, #259
add tests for url_is_from_spider() with allowed_domains
pylint clean-ups for test_utils_url.py
remove over-testing and dict testing for test_utils_url.py
doc: add comment about commit history cleanliness
sep-019: fixed typo
log (just once) when duplicate requests are filtered out. closes #105, #249
Merge pull request #261 from stav/allowed_domains

allow spider allowed_domains to be set/tuple, #259
added link to python binary libs, for windows installation
minor updates to contributing doc