[webui] the cool kids use haml, we should too
[webui] improve the subprojects view code a bit and write test cases

fixes #204 (well, not really - it just proves it was fixed before)
[api] do not stop delivering notifications if one is problematic

the OBS ran into a situation where several delayed jobs tried to deliver
notifications and always stopped when they ran over an even that was already
sent by another - and stopped there. But this caused a race to go on
[activexml] don't bother deflate for webui->api communication

(as long as we still do that)