Onscreen IDE & dynamic instant update [_v0.5.4_]

UPDATES :
[X] fixed document’s changed-after-saved status upon undo/redo
[X] improved “welcome screen” interface on Linux, so you can keep holding down ENTER/RETURN for 1 second to open the last edited files.
[X] improved “open recent files” interface :
1 added files removal
2 now uses report-view wx.ListCtrl, so you can multi-select its items easier than using wx.CheckListBox and you can sort it by name or location
[X] 1.6.0-messenger ready : fixed myFinder.crushInstance and myFinder.cleanup for not removing “_messengerId” attribute, so all unneeded events are correctly ignored.