Beta 0.6

CHANGES TO CONQUEST.JAVA
Moved screen parameter setting-related commands to the
setScreenParameters() method, called from the constructor.
btnCapture is now initially disabled.
Added method checkPossibleCapture(), calls the findCapturePoint()
method. If findCapturePoint() returns true, btnCapture will be enabled.
Fixed upgrade button not mapped to relevant unit bug.

CHANGES TO CONQUESTMAP.JAVA
Added capture point location arrays.
Added initCapturePoitns method. Called from constructor.
Added findCapturePoint() method.

OTHER CHANGES
Changed map to have 4 black squares. These are capture points.