Bumped version number to 2.3.0
Synchronize Command

- Added the stub of the sync command.
Backlog

- Added backlog handling for add/modify.
Unit Tests

- Removed mention of synch.key from all unit tests.  This is an obsolete file.
Code Cleanup

- Removed last traces of synch.key.
Sockets

- Migrated taskd socket code, for client-side transactions.
Messaging

- Migrated taskd messaging code over, for client-side communications.
Diagnostics

- Added server info to the diagnostics command output.
Sync

- Added a ::send method to CmdSync to perform the transfer.  Note that this
  does not yet include any TLS.
Sync

- Implemented the high-level communications, still without TLS.
- Includes temporary diagnostics, and unlocalized error messages.  These will
  converge upon proper and useful error messages as the command matures.
Sync

- Properly marked sync command as not displaying IDs, therefore no GC.
Statistics

- Added a backlog transaction count to the statistics.
Sync

- Added server credential handling.
- Added server error handling.
- Added task download handling.
- Added backlog truncation and synch_key handling.
- Added display of server-side messages.
- Cleaned up NEWS file for 2.3.0.
- Removed duplicate info in diagnostics command output.
Feature #934

- Feature #934, supports 'reserved.lines' to indicate a multi-line prompt for
  use in conjunction with 'limit:page' (thanks to Robert Gill).
- Removed 'locale' from the taskrc.5 man page.
- Added verbosity token 'sync'.
- Fixed bug in size calculation for 'limit:page', but there is still one more.
- Corrected unit test limit.t given the above fix.
Sync

- Corrected handling of backlog.data after a synch, using TF2::clear_tasks.
TDB2

- Added an option to bypass backlog recording to TDB2::add and TDB2::modify.
  This is required when handling backlog data, to prevent perpetual syncing.
Sync

- Distinguishes between new upstream tasks and deltas.
- Handles 201 (nop) code from task server.
- Removed unnecessary \r\n from messages.
- Cleaned up some of the diagnostic output.
Sync

- Provided protocol version in sync message.
- Improved feedback messages.
Sync Feedback

- Added a detailed sync summary message, indicating what happened.
- Improved and localized the feedback messages for the sync command.
- Added color to the add/modify feedback, matching the merge command.
- Enabled the sync timer for debugging output.
Sockets

- Suppports IPv4 and IPv6 task server addresses.
- Cleaned up error message when server is not available.