Cliquery

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- added further troubleshooting to IOError when adding/deleting bookmarks
- more replacements of 'http://' in with startswith('http://')
- url_quote (aka urllib.quote_plus) no longer called with bookmark flag
- fixed bookmarks add/remove after quote_plus change
- added from __future__ import absolute_import for explicit relative imports
- added more keywords to setup.py

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- removed import utils from cliquery unit test

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- added .travis.yml to test build and requirements.txt which holds list of dependencies

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- no longer triggers no search terms error if flag is 'open' to allow for plain browser open

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- added return statements to all functions in search()
- added test_cliquery.py unit tests
- switched 'http://' in url to url.startswith('http://'), same for https

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- minor wording changes to installation instructions