Creation of the demo home button

(references #80)
Creation of an empty "Open demo" dialog box

(references #80)
Make project preview widget as a reusable component
Implementation of the "Open demo" dialog box

(references #80)
Merge branch 'develop' into devel-market
Add of user choice for dependencies selection

* Added question dialog before the selection of dependencies
* Fixed asking window display when package has dependencies
* Adapted window text to the action
Fix of asking window display

* Added test to select dependencies if action chosen is not applied on them
Add of package name into the dialog message
Center of dataset package name in the selection page
Set getTypeName() as static method
Add of dependencies in tooltip
Add of dependencies list in message window

* Added name of dependencies to select
* Changed PacksToSelect list into map