correct SeaGenerator and some Boundary tools

use high precision in Way.clockwise() and Way.containsPointsOf()
This reduces the number of messages like
" Converting anti-island starting at ... into an island as it is surrounded by water"

The routines are not used to calculate precompiled sea data or precompiled boundary data, but they are used in tools like
BoundaryCoverageUtil, BoundaryDiff, BoundaryFile2Gpx
and to debug boundary data, so there is no need to 
create new precompiled data because of this change.





git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3109 25d90789-57f7-4ee0-8453-03a3dfeeeb22