Port filter_example module to Drupal 8

Port of the filters and the tests (which pass, even). hook_help() and hook_menu() stuff not yet included.

And here it is with hook_help().

Assuming we can neglect the stuff that hook_menu() was doing (see my post in the D8 port meta-thread about that), this should be complete now.

Pretty sure we can't neglect what hook_menu was doing. :-)

Testbot makes me unhappy.

Huh?

I would love to work on this starting from the beginning.

This need a lot of work to be done as Drupal 8 uses plugins.Also the tests need to be written from start. Will try to make a sandbox project and proceed further.

All the development related to this issue is being done over here: https://www.drupal.org/sandbox/zealfire/2444489

Generally unassigning issues. Please re-assign yourself as desired.

This can be marked duplicate or closed in favour of #2277629: Add filter example. As the patch contains both port and test.

#2277629: Add filter example is a lot more complete. Closing this issue and rescoping there.