Added support for Language Culture Name

[thorsten]

I'm submitting a ...

[ ] bug report => check the FAQ and search github for a similar issue or PR before submitting
[ ] support request => check the FAQ and search github for a similar issue before submitting
[x] feature request

Current behavior
getBrowserLang() returns just the language code, e.g. "de" or "en". In our current project there's the need to use the language culture name, e.g. "de-DE" or "en-US".

Expected/desired behavior
Add a new function getBrowserCultureLang(), that returns the language culture name, e.g. "de-DE"

What is the motivation / use case for changing the behavior?
The need in a project for this feature.

Please tell us about your environment:

• ng2-translate version: 3.1.0

• Angular version: 2.1.0

• Browser: all

• Language: all

[chpasha]

the methods getBrowserLang and getBrowserCultureLang have 99% same code or do I miss anything? getBrowserLang should actually reuse getBrowserCultureLang and split result with - or _

[thorsten]

Yes, you are right. Good hint. @ocombe, should I add another PR with this improvement?

[ocombe]

yes please :)