fix(forms): reverted back to old checkboxes as the new ones are broken and missing clear state, fixes #4096

Matt weekend ui

ux(): added lines backgrounds, did not add them to the page background, could not make them look good / fit in without being distracting

ux(): tweaks and polish, and also simpifying width classes, gf-size-xxx and gf-size-max-xx are now width-(1-30), and max-width-(1-30)

created secondary button style, added a couple of variables, played with the plugins page to get the underline in place. Worth a look, but check that I was building everything properly :)

added angular gradient to page and login. Tweaked header underline to not be so heavy. Tweaked stacked logo on login. Created an alternative to avatar when there's no connection to gravatar - could use work, but I think you get the idea.