Fix some bugs in in-place editing: (1) errors from freopen were not reported correctly (2) large files were not handled correctly (3) read-only files broke things
Fix some bugs in in-place editing:
(1) errors from freopen were not reported correctly
(2) large files were not handled correctly
(3) read-only files broke things

MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase