Bugfix: load and settigns buttons (#36)

The load and settings buttons in the main menu now work correctly
Bugfix: Citizens in buildings were not saved (#38)

Only the total amount of inhabitants was saved. That lead to double
citizens when loading a city.
Bugfix: more citizens while pausing or new game

The number of citizens went up even when the game was paused or  a new
game was started.
Minor changes to the BuildingTask
Added gui for building information (#9)

When a building is clicked a new panel shows up with further information
about the building.
Bugfix: camera moving up while building (#42)

When buildings were built before the camera wiggle animation was
finished, the cameras Y position permanently changed.
Changed money info coloring + bugfix

The money label now turns red when in build mode and the current
building is too expensive. Also, a bug that caused the fps to drop while
the buildings info panel was displayed was fixed.
Improved money label (#41)
Merge pull request #44 from ForceField-IndieGames/Benedikt

Building info panel + Bugfixes