Add AUD Currency

[TechJedi90]

Please add the AUD Currency into Tracktor.

Love the idea of this app - Far better than some of the others that I have used!

[tsbates]

I think a better approach would be to change USD to 'dollar', which would apply to Australia, America, New Zealand etc.. The symbol doesn't change, just USD in a files files.

[javedh-dev]

Fixed in #88