Emit better sync error message
Less progress message on sync
Fix time zone converter
Abort if sync process has too many items to sync
Fix off-by-one error on calculation of X-SC-Duration
Add X-SC-Recurrence/Mission-Tag into iCaledar using X-property
Introduce fine-grained sync control

Now sync-strategy handles 16 states, formerly used to 9.
Add tests
Remove garbage debug code