Add so much more support!

- PHP 7+
- Laravel 6+

Update to new method signature from laravelcollective/html

Add package auto discovery (thanks @tortetorche!)

Support newer laravelcollective/html

Add support for laravel 5.4

This is likely to be the last release of this particular instance of …

…the package!

I am planning on moving Bootstrapper to a seperate list of packages - which should hopefully help the inevitable bootstrap 3 and bootstrap 4 problems that we'll face in the coming months.

Merge branch 'update-html-dep'

Merge pull request #300 from rawrmonstar/features/table-custom-classes

tdClass Feature

Fix Issue with incorrect resolution

Force resolution of HtmlBuilder

Force a resolution of the correct HtmlBuilder as a work around until
Laravel 4 support is dropped. Closes #279, closes #292