Allow marking files for diffing from explorer

[GoogleCodeExporter]

Currently the "Diff" command only shows up in the explorer context menu if two 
files are selected, or one file that's versioned and modified.

This works for most situations, but to compare two files that are not in the 
same directory, starting the diff from explorer is not possible.

diff-ext (http://diff-ext.sourceforge.net/screenshots.shtml) is an extension 
that can do this.

Implement something similar in TSVN to start TortoiseMerge.

Original issue reported on code.google.com by tortoisesvn on 20 Nov 2013 at 8:24

[GoogleCodeExporter]

Note: since the context menu shell extension (or any shell extension) is not 
guaranteed to stay in explorer memory, we have to save the files marked for 
later comparison somewhere, e.g. the registry.

And we have to find a way for the user to clear the list of files marked for 
comparison, otherwise that list will get too large over time and the selection 
submenu too crowded.

Original comment by tortoisesvn on 20 Nov 2013 at 8:26

[GoogleCodeExporter]

Original comment by tortoisesvn on 4 Dec 2013 at 7:15

• Changed state: Started
• Added labels: Milestone-1.9.0

[GoogleCodeExporter]

Adding an entry "Diff later" which stores the path of the selected file,
and another entry (shown if a path is stored) "Diff with \"path\"" that then 
starts the diff viewer with the current path and the one stored.

Original comment by tortoisesvn on 4 Dec 2013 at 8:52

[GoogleCodeExporter]

This issue was closed by revision r25027.

Original comment by tortoisesvn on 5 Dec 2013 at 7:53

• Changed state: Fixed