Dirty.php: record delete is handled - if lock exist, delete is not allowed.

Dirty.php, QuickFormQuery.php: Update user messages. Renamed releaseDirty() to checkDirtAndRelease()

Manual.rst: add documentation for record locking
DatabaseUpdateData.php: Add new column 'dirtyMode'
Dirty.php, Config.php, formEditor.sql: remove dirtyMode=readonly. Rename 'timeout' to 'exclusive' and 'overwrite' to 'advisory'.

Add Message if dirtRecord is missing.

Fixed some 'unknown index' issues - deny save in a first version works.

First version for save - not working now.
Manual.rst: document config var SYSTEM_DIRTY_RECORD_TIMEOUT_SECONDS.
QuickFormQuery.php, Dirty.php: extend to support QFQ/save().
Client.php: fixed broken PHP Unit test
Config.php: set default for dirtyRecordTimeout.
BuildFormBootstrap.php: No dirtyUrl if dirtyMode=none.
formEditor.sql: extend definition to Form.dirtyMode, new table 'Dirty'
Fixed several unit tests for new tables.

typeahead.php: An exception catched in typeahead.php has been assigned as array element, instead of a whole array. Fixed.

First implementation on server side: only tag as dirty, no check during save().
dirty.php, Dirty.php, Client.php: new
Store.php: refactored fillStoreClient() to use an dedicated class.
BuildFormBootstrap.php: add hook for dirty.php