Function toFixed

toFixed(value: number, precision?: number, round?: number): string
Implementation of toFixed() that treats floats more like decimals.

Fixes binary rounding issues (eg. (0.615).toFixed(2) === '0.61') that present problems for accounting- and finance-related software.

Usage:
```
// Native toFixed has rounding issues
(0.615).toFixed(2);
// => '0.61'

// With accounting-js
toFixed(0.615, 2);
// => '0.62'
```
Parameters
- value: number
  Float to be treated as a decimal number
- Optionalprecision: number
  Number of decimal digits to keep
- Optionalround: number
  Decide round direction
Returns string
- Given number transformed into a string with the given precission