* add new addOptions option
* replace defaultOptions with addOptions for all extensions
* replace defaultOptions with addOptions for all demos
* replace defaultOptions with addOptions in docs
* refactoring
* refactoring
* drop object support for addOptions
* fix optional options
* fix tests
Use the extension name when initializing the
LowlightPlugin. In this way, several extensions
can make use of the same plugin
Co-authored-by: Enrique Alcantara <ealcantara@gitlab.com>