Fixing KeyError that arises 'a' tags are missing hrefs

Though I have no idea why this happens when a page is retrieved by script and doesn't seem to in the browser's source view.
Merge pull request #45 from indraastra/master

Fixing KeyError that arises 'a' tags are missing hrefs
dont re-use the parser variable name
dont crash if a lecture has not associated video (e.g., in genes-001), fixes issue #48
Added long path trimming option to avoid long path issues in Windows
update log msg
Merge branch 'master' of https://github.com/ilfats/coursera-dl into ilfats-master
refactored trimFileName into a function and enabled trimming by default on windows
bump version
Update README.md
Merge pull request #60 from olivierkes/master

Updates README.md: -d became --path