Merge pull request #142 from Bumanji/master

Fix variable names and method names on MainWindow and ModelOverviewWidget classes
Minor fix: Overview widget is closed together with the main window.
Merge pull request #143 from Bumanji/master

Fixed a bug about operation list's item name converted to UTF-8 twice.
Updated fr_FR translation
Merge pull request #144 from babs/master-trans-fr

Updated fr_FR translation
Introduced the pgModeler wiki access through main window.
Set mainwindow -> File menu -> Save All invalid default.