v2.0.0 - Conversion to TypeScript

Converts the code to TypeScript, and restructures the exports:

Breaking:

• Default export converted to named export. Use import {r} from 'regexr' instead of import r from 'regexr'.
• Helpers and regexes no longer added to the r function, but as exported separately. For example use import {escape} from 'regexr'; escape(...) instead of import r from 'regexr'; r.escape(...), and import {identifier} from 'regexr/regexes'; identifier instead of import r from 'regexr'; r.identifier

Features

• new e alias added for escape: import {e} from 'regexr'; e(someString)