Decimaljs

* 28/09/2020
* Correct `sqrt` initial estimate.

* 08/05/2019
* 128 Workaround V8 `Math.pow` change.
* 93 Accept `+` prefix when parsing string values.
* 129 Fix typo.

* 27/02/2019
* Check `Symbol` properly.

* 26/02/2019
* 122 Add custom `util.inspect()` function.
* Add `Symbol.toStringTag`.
* 121 Constructor: add range check for arguments of type number and Decimal.
* Remove premable from uglifyjs build script.
* Move *decimal.min.js.map* to root directory.

* 13/12/2018
* 114 Remove soureMappingURL from *decimal.min.js*.
* Remove *bower.json*.

* 24/05/2018
* Add `browser` field to *package.json*.