Add warning in Javadoc of AreaAdapter regarding AreaFile.  Add real getSubpoint() method to GMSX nav.
Merge pull request #7 from tomw2/satnav

Update AreaAdapter javadoc.  Add getSubpoint() method to GMSX nav...
lose redundant PI declarations in nav code
Merge pull request #8 from tommyjasmin/master

Lose redundant PI declarations in nav code.