update define and includes in power_event_handler

it's not a QApplication anymore
implement skeleton for new application class

inherits QtSingleApplication. Created to ultimately handle phone and focus
events. Empty class for now. No functionnal change.
handle dial and focus requests in EventAwareApplication

goal : give focus to already running instance when launching new
instance and shallbeunique configuration
improve readability of argument parsing in main:init_xivoclient
abstract fileopeneventhandler in EventAwareApplication

no need to have multiple interfaces to handle focus depending on
platform. EventAwareApplication is now the only interface.
rename signal dialNumber to dialnumberreceived in FileOpenEventHandler

make signal name coherent with Qt conventions
Add (temporary) Debug

WinBlows! :?
Revert "Add (temporary) Debug"

This reverts commit b84bd0a20dd1e0304c4e6bd8d64d285577b2c004.
silence the compiler
Merge remote-tracking branch 'origin/5225-focus-on-relaunch'