added apiserver and api client implemenation of change password.

Added the change-password user command
feedback from review

added more tests to the change-password command
Added --generate and --password flags.

Try to revert the password if the environinfo write fails
client side of NetworkInterfaceWatcher
cleaned up the change-password jenv file interface, simplified the usermanager test

use readpass from latest utils
the first implementation
Refactor Action, per new names.ActionTag changes, and to improve internal structure
Merge remote-tracking branch 'upstream/master' into 122-state-machine-watchinterfaces
changed to WatchCollection
no more TxnRevno exposed in networkInterfacesDoc
change StringsWatcher to NotifyWatcher
change _id string to _id bson.ObjectId
Increment devel to 1.19.5, which 1.18.x will accept as an upgrade option.
more complicated test
Merge remote-tracking branch 'upstream/master' into 122-state-machine-watchinterfaces
enable dynamic network interfaces
Merge remote-tracking branch 'upstream/master' into 121-networkinterfaceswatcher
merge latest from trunk
change StringsWatcher to NotifyWatcher
update bodie's code with new signatures