Improvements and fixes — Towers Heritage Steam update #1421539

Thanks for your feedbacks ! This is a patch to address some of them. ImprovementsLog messages are written in a dedicated window, to stop spamming the game view. Space bar put the game in pause. Keyboard button L launch the next wave. Camera's movement is nicer (the speed ot the camera is linear when using either arrows keys or the screen border, instead of having a small acceleration) CorrectionsSometimes, when clicking the button to send the next wave, the next wave was sent followed a few second later by another one. Scroll of Scout report window is quicker. The selection of a unit when the game is paused is no longer a multiselection.