Unit building: Planet list works.
Implement unit building on a branch halfway through
Implement unit building on a branch basic unit building finished.
Implement unit building on a branch implement build button on planet window halfway, must set planet selected on planet_list and city selected on city_table.
Implement unit building on a branch implement build button on planet window halfway, must set planet selected on planet_list and city selected on city_table. Include Faction.java should have been included two commits previous.
Add build button to planet window.
Implement input units halfway through.
Implement input units code written debugging remains.
Implement input units code written debugging almost finished.
Implement city panel halfway through.
Implement basic unit building finished.
Merge unit_building with master
Update README. Edit, :oops: conflicting files in previous commit:

       both modified:      src/galaxyreader/Structure.java
       both modified:      src/galaxyreader/Unit.java
       both modified:      src/game/Faction.java
       both modified:      src/game/Game.java
       both modified:      src/gui/Gui.java
       both modified:      src/gui/PlanetWindow.java
       both modified:      src/state/State.java
       both modified:      src/util/C.java
       both modified:      src/util/Comp.java
       both modified:      src/util/Util.java
       both modified:      src/util/WindowSize.java