Added a test to see if clone would duplicate the session. It does.

Subclassed DateTime's from_object method, which was secretely deleting
the internal session variable.  There is probably a more robust way to
do this, such as by "...implementing the utc_rd_values() method as the
from_object docs suggest.
Finished fixing the bug with time zone errors in editing an event.

docs/changelog/7.x.x.txt

@@ -2,6 +2,7 @@
  - fix: Checkbox is no longer available when creating custom profile fields
  - fix: profile fields do not ever set the default value
  - fix: CS email message shows up as an attachment
+ - fix: Calendar: start/end date time off in edit interface (perlDreamer Consulting, LLC)
  
  
 7.3.5