Replace marked with marked3

[mortenn]

marked seems quite dead, unfortunately, but someone forked it and made marked3, which is actively maintained.

If this could be updated to use that, it would be swell :)

[Hypercubed]

Hi.. I created an initial version for commonmark here: https://github.com/Hypercubed/angular-commonmark. However, as I have mostly moved to angular 2+ I haven't had time to update this lib.

[mortenn]

Hi,
I prefer to keep the amount of dependencies to a bare minimum, so moving to something that has 4 deps is not that great, imo.

A bigger issue is the fact that npmjs.org gives me a 404 if I try installing angular-commonmark, however.