[patch] Fix OS X Compilation

[David A. Riggs]

Attached, please find an 'svn diff -u' patch that should fix
compilation and build on Mac OS X (tested only with OS X 10.5.5, wxMac
2.8.9). The only significant code change is that it renames the Point
class to SurvexPoint to avoid a naming conflict. Apply to the
survex-1_1 svn branch.

I've also built an Aven.app on my local machine, but have not included
it in this patch yet, as it's got a few more kinks to iron out - I'll
have time to look at it again early next week, and will send another
patch then.

- DR

-- 
David A. Riggs <david.a.riggs at gmail.com>