Convenience functions for easier time tracking.  Provides commands
for changing timestamps directly from the agenda view.

`org-clock-convenience-timestamp-up' and
`org-clock-convenience-timestamp-down' can be used to modify the
clocked times in and agenda log line in steps (same as on
timestamps in a normal org file). `org-clock-convenience-fill-gap'
modifies the timestamp at point to connect to the previous/next
clocked timestamp. `org-clock-convenience-fill-gap-both' will fill
the gap of both the starting time as well as of the ending time of
the time range in the current agenda log line. Also provides a
number of utility functions to work with and find/analyze
timestamps.