Added the method BaseObject::isCodeDiffersFrom to compare the xml code
between two objects

Added methods to retrieve objects by their name on DatabaseModel class.
Added a basic structure for model database sync form

Added some conditional compilation flag to deactivate some features for
demo version.

Minor fix on DatabaseImportHelper to accept a DatabaseModel instance
instead of ModelWidget.

Minor adjustments on deployment scripts.
Minor adjustment on deployment script to correctly rename the demo
packages.
Minor adjustment on windeploy.sh
Minor adjustment on macdeploy.sh
Minor change on example.dbm file

Minor fix on conditional compilation macros entries for demo version
Merge branch 'model-db-sync' of https://github.com/pgmodeler/pgmodeler into model-db-sync
Minor fix on Messagebox class when replacing <br> tags on message text.
Minor adjustments on demo version code
Added the ability to save the dock widgets configuration on the main
config. file
Merge branch 'dock-wgts-conf-saving' into model-db-sync
Fixed a bug on xml parser when reading DTD files from paths that
contains accentuated chars (issue #525)
Merge branch 'fix525-path-error-xmlparser' into model-db-sync
Minor ajdustment on demo version code.
Fixed a bug on relationship validation process that was causing errors
mainly related to generalization relationships (issue #526)

Sync action renamed to Diff, as well forms related to it.

Update on several images.
Fixed the bug that was preventing a sequence to be assinged to the
column. (issue #529)

Minor widgets adjustment on modeldatabasediffform.ui, modelexportform.ui
and databaseimportform.ui
Fixed a crash when creating relationships. Apparently this crash was
caused by a faulty access on some threads right after close the
relationship dialog. (issue #528)
Added the ability to create special primary key on many-to-many
relationships

Fixed a infinite loop on operation list class when calculating the chain
size.
Added the classes to control the model-database diff operations.
Schemas by default will be created to show the bouding rectangle.

Added the method Catalog::getObjectsOIDs in order to retrieve all
database objects oid and store them in maps. This method is used as an
auxiliary for model-database diff process.

Minor improvement on BaseObject::getTypes() in order to exclude some
types from the resulting vector.

Added the method ConnectionsConfigWidget::fillConnectionsComboBox() in
order to reuse the code that fills up a combobox with configured
connections.

ModelDatabaseDiffForm implementation checkpoint.