v0.8.7 - Minor improvements

Another 'housekeeping-release'. 

The Selection-/Highlighting-System was improved, hopefully this will help with the known issue mentioned below

Known Issues

• Under certain circumstances, when choosing a Floor, the Selection System asks multiple times for input, causing an issue with any further selections.
• When throwing a potion during combat at a point in time close to the countdown reaching zero, the item appears to be used but is not. It is lost afterwards. 
• Throwables might look like they are not hitting their targets sometimes. But in the game logic, the throwable always hit. 
• Current Drag&Drop implementation is unintuitive. You don't always know if, when and how it works. 
• Visualization of 'Combat Spectators' looks off if there is a Wall/ no Floor at the west side of a room.