tracbuildbot/buildbot_api.py: BuildbotConnection._request() improved retry and exception message.
tracbuildbot/buildbot_cache.py: BuildbotCache.cache_builder() added ignoring build if fail to get it.

async_buildbot_cache_worker() - improved exception log.
tracbuildbot/htdocs/js/buildbot.js: fixed revision ref.
Merge remote-tracking branch 'remotes/origin/master' into develop
tracbuildbot/timeline.py and /htdocs/js/buildbot.js: changed revision ref style.
tracbuildbot/buildbot_api.py: BuildbotConnection._parse_build() fixed error log detect.
tracbuildbot/admin.py: fixed saving repo name.
tracbuildbot/web_ui.py: BuildbotBuildHandler() fixed build calling for builders with space in name and try to add some info to alerts on build pending fail.
tracbuildbot/web_ui.py: fixed build alert.
tracbuildbot/buildbot_api.py: BuildbotConnection._request() improved exception message generation.
Added missing tracbuildbot/htdocs/img/bgBuildTitle.gif(ref from tracbuildbot/htdocs/css/buildbot.css).
Merge branch 'develop'