Find in multiple files: add "Mark source files in project" option

[vix]

I usually add a lot of files to my project (images, documents, ...) because in this way their path is taken as a relative path when building a distribution kit.

But in this way, if I press "Mark files in project" all the files are marked to search in, and so CVI gets a lot of errors for the files that can't be opened because they are not text files.

Using "Mark all c" and "Mark all h" extends the research also inside CVI installation directory, and (usually) this is not what I want.

I propose to replace "Mark files in project" with "Mark source files in project" or to add this last option to the existing ones.