Simplify (and avoid edge cases) in other code by having
ReadHistory manage the "lastfile" setting on add, remove,
rename...
Fixed a few other cases of things not updated.
Bump base for util.fsyncOpenedFile() and util.fsyncDirectory().
Use these to force flush to storage device when
saving luasetting, docsetting, and history.lua.
Also dont rotate them to .old until they are at least
60 seconds old.
Also make auto_save_paging_count count right.
Also bump crengine: open (as text) small or empty files
This commit standardizes the various todos around the code a bit in a manner recognized by LDoc.
Besides drawing more attention by being displayed in the developer docs, they're also extractable with LDoc on the command line:
```sh
ldoc --tags todo,fixme *.lua
```
However, whether that particular usage offers any advantage over other search tools is questionable at best.
* and some random beautification
Made the onHold buttons table similar to the one of File browser.
Added "Purge .sdr" and "Delete" to these buttons.
Moved the purgeSettings and removeFileFromHistoryIfWanted
logic into filemanagerutil functions.
Stay on the same page when manipulating history (previously, we were
always put back on first page).
Really keep deleted files in history (unless setting says otherwise).
Show deleted files in grey or dimmed in classic History and all
CoverBrowser display modes.
