added header files to hold Unix flavor-specific config settings; also thrown out the unused fseek64 macro from both Unix and Windows syspovconfig.h; should fix GitHub issue #9.

corresponds to Perforce changes 6129, 6131, 6133.
eliminate uint type from platform-independent code; fixes GitHub issue #10

corresponds to Perforce change 6130.
now using std::tr1 smart pointers if available, or boost's implementation otherwise; we're using <boost/tr1/memory.hpp> to pull in either. Should fix GitHub issue #8.

corresponds to Perforce change 6132.
fix GitHub issues #5 and #6.

corresponds to Perforce changes 6135, 6136.
attempt to fix GitHub issue #7

corresponds to Perforce change 6137.