[core] Decode environment variables with filesystem encoding (Fixes #3854, Fixes #3217, Fixes #2918)

Introduces compat versions of os.getenv and os.path.expanduser
[utils] Add posix expanduser implementation and clarify the original source
support zsh completion
add zsh completion support into Makefile
[ard] Add rss support
Fix ndr.de outdated test url
Merge pull request #3921 from Dineshs91/ndr-fix

Fix ndr.de outdated test url
Replace 404 url
Fix download error in GooglePlus
Merge pull request #3924 from Dineshs91/googleplus-fix

Fix download error in GooglePlus
[googleplus] Modernize and extract all formats
Merge pull request #3923 from Dineshs91/howstuffworks-fix

Replace 404 url
[vimeo] Make the protocol mandatory in the url (fixes #3926)

If it's missing, it will be correctly handled by the generic IE.
[mixcloud] Fix metadata extraction (fixes #3930)
[theonion] Add new extractor (closes #3928)
[theonion] Fix a small mistake in string formatting
Description changed
Merge pull request #3932 from Dineshs91/ndr-fix

Description changed
[niconico] Fix ignored --netrc flag

See issue #3753
release 2014.10.12