Base: App Circle sidebar (add support floating window)

PS.8 : rebased
PS.9 : add support minimize/maximize window

Change-Id: Ied388a0a4054dfaf1d3e6fcdc33dd5aab28565a9
[Patch 9] Base: App Circle sidebar (add support floating window)

PS.8 : rebased
PS.9 : add support minimize/maximize window

link: https://gerrit.omnirom.org/#/c/6515/