feat(currencyFilter): add numbers after dot count parameter

So we can format currency numbers like this:
expect(currency(1234.5678, "USD$")).toEqual('USD$1,234.57')
expect(currency(1234.5678, "rub", 3)).toEqual('rub1,234.568')
expect(currency(1234.5678, "rub", 0)).toEqual('rub1,234')
The last case is usual for Rubles for example.