Change translation from Goslate to Google Translate API

[RNabel]

Reason:

• Goslate is abandoned, new translation mechanism needed

New features:

• translation using Google Translate API
• added parameter to specify Google Translate API key, (-K API_KEY or --api-key API_KEY)
• Reformatted autosub file to comply with PEP8
• EDIT: Source / destination language codes updated according to Google's docs and simplified the parameter from --list-(src|dst)-languages to --list-languages

Fixes:

• PicklingError #12

[agermanidis]

Hey, thanks a lot for this! Can you add the new library dependency to setup.py? After that I can merge this in.

[RNabel]

Hey, no problem!

I added the dependencies, and also updated the language codes according to Google's Translate Documentation as the other codes broke the translation (i.e. en-US-style did not work and was replaced with en-type codes).
Subsequently, the --list-(src|dst)-languages flags return the same codes, and I propose to simplify it to --list-languages.

Thoughts?

[agermanidis]

That looks good, but I wonder if we're losing transcription accuracy by not using the dialect-specific codes for the recognition (e.g. en-US). The Speech API is not very documented so it's hard to tell. What if you kept the source and destination codes and just passed self.src.split('-')[0] to the translator as src?

[agermanidis]

Did a few tests and it didn't seem like the dialect made any significant difference for the recognition accuracy, so I'll go ahead and merge this in, thanks again.

[RNabel]

Awesome! The README may also need updating. I'll have a look at that tomorrow.