Renamed plugin DummyPlugin to Dummy.

Created plugin Xml2Object to help develpment testings.
Minor improvements on PgModelerPlugin structure.

Finish creating the developer plugin Xml2Object.

Minor changes on ui-style.conf
Merge pull request #208 from babs/pgsql9x-support-trans-fr

Pgsql9x support trans fr
Fix a bug that was preventing a new model to be saved.
Fixed a bug on 'Save as' command
Minor fix to permit the correct visual update of schema rectangle when
adding a column on a table.
Restored object selector icon.
Minor changes on FK relationship creation.

Changed the way that user-added fks has code generated.
Minor changes on FK relationship creation.

Changed the way that user-added fks has code generated.
Merge branch 'pgsql9x-support' of https://github.com/pgmodeler/pgmodeler into pgsql9x-support

Conflicts:
	libpgmodeler/src/databasemodel.cpp
Fixed the wrongly commited databasemodel.cpp file.
Fixed segmentation fault on startup (windows only)
Minor fixes on ui-style.conf
Added "Recent Models" menu.
Model validation code checkpoint.

Minor fix on OperationList
Added support to hide relationship labels and table extended attributes.
(issue #211)

Minor fixes on ModelValidationHelper
Fixed glicthy wheel scroll/zoom. (issues #213)
ModelValidationWidget finished. Pending code comments.

Minor fixes on database model code generation.
ModelValidationWidget code comment done.
Simplified the method DatabaseModel::loadModel(). The method does not
try to recreate a object when some dependency was not found instead
errors are raised.