[Ohrrpgce] SVN: teeemcee/11533 Add lazyclose, alternative to CLOSE which keeps the file open so another

[subversion at HamsterRepublic.com]

teeemcee
2019-12-30 22:00:04 -0800 (Mon, 30 Dec 2019)
386
Add lazyclose, alternative to CLOSE which keeps the file open so another OPENFILE can reuse it.

This is a significant speed-up on Windows, when opening and closing is slow --
especially if a virus scanner is invoked every time!

And close_lazy_files to ensure files are closed. It's called when renaming,
copying, or deleting files/directories, so should not be required anywhere else.
---
U   wip/filelayer.cpp
U   wip/filelayer.hpp
U   wip/filetest.bas
U   wip/lumpfile.bi
U   wip/mutex.hpp
U   wip/util.bas