Fix url retrieval

See http://www.w3schools.com/jsref/prop_doc_url.asp
This refs #281
Merge pull request #334 from ombre42/url-in-window-info

Fix url retrieval
add default prefix and support prefixes with spaces
fix unit test for bad prefixes
Pass window.id through if not None
thank the thankless
Merge pull request #336 from ombre42/window-ids-unexpected-type

Pass window.id through if not None
Fix url retrieval

See http://www.w3schools.com/jsref/prop_doc_url.asp
This refs #281
Merge remote-tracking branch 'upstream/master'

Conflicts:
	CHANGES.rst
	src/Selenium2Library/webdrivermonkeypatches.py
improve doc for default locator prefix
fixes #200

Totally unrelated change I know.
typo in default strategy doc
Merge branch 'spaces-in-locator-prefixes' of https://github.com/ombre42/robotframework-selenium2library into ombre42-spaces-in-locator-prefixes
Merge branch 'ombre42-spaces-in-locator-prefixes'