add TypeScript support

[tokkoro]

I've added a basic support for TypeScript language.

ps. This is my first pull request and all feedback is welcome!

[dolanmiu]

Please merge this in, I need this in my project!

[tokkoro]

@dolanmiu It's open fork and branch, so you can use it without official pull. Please report any problems you have with this typescript patch.

[adam-waldenberg]

Hi. Like most other pull requests, this will be merged in conjunction with the next release. This will also give everybody time to find potential problems.

[nfode]

You forgot to add the extension to gitinspector/extensions.py.

[nfode]

@adam-waldenberg If I may ask when is the next release?

[piizei]

@tkok89 Could you add .tsx to the file extensions as well?

[ozra]

Yeay! ts and tsx - definitely needed! :-)

[ozra]

Öppen snart ett år? @adam-waldenberg