add start/end_date attributes to corporation objects -- currently only relevant for corporation objects created via a ->corporations method on a character object
provide a descending sorted list of corporations (done before) with start/end membership dates for the character (new with this commit)
add 1 second to corporation membership start timestamp (the need for this is not documented anywhere in CCP's docs, but based on several of my own characters' histories, it appears to be necessary)
0.07 version bump and Changes entry