restored sanity checks on int() InternalTip
update API, coherent support of receiver confs
last_activity of internaltip cleaned approach
implemented total delete in Tip
minor fix and cleanings
implemented model and handler for receiver plugin configuration
extended shooter to support receiver configs #23
implemented tests for receiver confs
random GUS generation unrandomized in TESTING mode
completed Receiver API and config activation
rewritten notification scheduler with the plugins configuration
updated notification plugin design
updated mail notification plugin #29
minor cleaning and enhancing in models/tip
implemented test for plugin, admin and receiver configuration
Merge branch 'fileflow' of ssh://github.com/globaleaks/GLBackend into testnodeandrefactor
minor corrections