recognize when file is changed on disk

[szabgab]

Recognize when file is changed on disk
and ask user if what does she want to do?

Sspecially important to do this before saving file.

[szabgab]

it is alrady done before saving the file

it should be also done when a document gets focus

and optionally every time when a document is changed.

[jquelin]

monitor open files on a regular basis (every 10 seconds?) and popup user asking to reload / ignore.

if user chose to ignore and file changes again on disk, either popup again or ignore till next save or reload.

[jquelin]

r1036 - check done every 5 seconds