Added Swedish (sv) i18n.
Added URL encoding to OTP auth URL

Google Autehnticator gave an error when scanning the code using the
previous format. I added url quoting as well as the optional `issuer`
URL parameter.
Modified otpauth label format

Changed from `Site Name (username)` to `Site Name:username`, which
appears to be the most common format, althoguh both would probably
be valid.
Updated test cases

Modified test cases to reflect the changes made in `QRGeneratorView`
and `get_otpauth_url` (otpauth label and issuer parameter)
Modified urllib import to support Python 3 as well.
Fixed indentation and coding style issues
Merge branch 'feature/otp-auth-url' into develop
Merge branch 'feature/sv-i18n' into develop