TileConstants: isConstructed() returns true if tile >= ROADBASE

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@783 d9718cc8-9f43-0410-858b-315f434eb58c
getPollutionValue: use isFire and isRadioactive instead of comparing numbers

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@784 d9718cc8-9f43-0410-858b-315f434eb58c
getPollutionValue: move to TileConstants

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@785 d9718cc8-9f43-0410-858b-315f434eb58c
cleanup: remove no-longer-used isBigZone()

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@786 d9718cc8-9f43-0410-858b-315f434eb58c
TileConstants: remove hardcoded tile values from OverlayMapView

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@787 d9718cc8-9f43-0410-858b-315f434eb58c
isRoad: fix bug in which the wrong variable was used

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@788 d9718cc8-9f43-0410-858b-315f434eb58c
isWire: fix bug in which the wrong variable was used

git-svn-id: https://micropolis.googlecode.com/svn/trunk/micropolis-java@789 d9718cc8-9f43-0410-858b-315f434eb58c