Fixed a *REALLY* annoying bug in Windows with the latest code.  It seems that System::PAGE_xxx enumerations were already defined elsewhere in a Windows header file.  This was very irritating to track down.  As a result, they're now named System::PA_xxx (for 'PageAccess').

The file selector in Windows now ignores all items starting with '.', not just the directories '.' and '..'.  This is most apparent when using the Windows port and browing Linux shares, which shows many dot files.

git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@2012 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba