External Resources: exclude/include all files

[yanne]

Originally submitted to Google Code by @Tattoo on 10 Dec 2012

It would be nice to exclude/include all external resource files with right-clicking the item "External Resources" in the tree and selecting "exclude all" or "include all", respectively.

Idea is that "exclude all" writes all file paths to exclude file. Therefore, if you have many external resource files, you can easily exclude all and include files in need-to-know-basis (and then re-exclude them).

This issue relates to issue 1152 which is concerned with excluding single files.

[yanne]

The mentioned issue 1152 is #1191 here.