fix up the package's import path

[bretkikehara]

Adds options:

1. appendPackageName - Appends package name on each import. Resolves issue Does not honor package config option in esdoc.json #4 and Improvement : remove package name #6
2. packageProp - Allow user to configure which package prop to use for imports. Resolves issue Unable to use single namespace #5
3. replacer - Allow user to set as a string or array.

Accepts package.json to be defined as an object.

See also esdoc/esdoc/pull/320

Moves doc generation into each test.