Optionally preserve drawers; set repeats via SCHEDULED/start

- Whitespace cleanup removes trailing whitespace at end of line (use diff -b to mask during review of pull request)

- Preserve property drawers when new customizable variable org-toodledo-preserve-drawers is true.  Property drawers will be stored in entry text when writing out to Toodledo.  They will be omitted when querying internally for entry text.  Without this modification, properties, particularly those added by other org modules are regularly lost in roundtrips to Toodledo.  One example of a drawer property worth preserving is ":STYLE: habit".  Note that to preserve the historic functionality the org-toodledo-preserve-drawers variable defaults to nil, but you may consider flipping that to t.

- Allow SCHEDULED/start to set repeats as well as DEADLINE, particularly when DEADLINE doesn't exist or has no repeat.