Merge pull request #431 from xnoise/master

Updated checksum file parser to support spaces in filenames
When synchronisation fails, show complete error message in a dialog.
Added basic PROPERTIES drawer support, to facilitate org-contacts support.
Added further PROPERTIES drawer functionality: make display of drawer contents a preference, allow customisation of which fields are displayed when.
Fix for issue #317.
Merge pull request #435 from flexibeast/issue-317

Fix for issue #317.
Merge pull request #434 from flexibeast/properties-drawer

Add basic PROPERTIES drawer support as a foundation for org-contacts support.
Merge pull request #433 from flexibeast/notifications

When synchronisation fails, show complete error message in a dialog.