Adding a cmake config to help find image resources

[matthewroberthenderson]

When debugging an an example app after first configuring the project the image paths cannot be located. Adding a simple in file could also be used for other relative project paths.

close #694

[ihhub]

Hi @matthewroberthenderson , the provided by you solution fails on Linux (see this).

Let's understand the root of the problem: I assume that images are not being copied together with source files during CMake configuration. Therefore, I suggest to add file copying part in CMake files and use relative path for images without modifying source files.

[matthewroberthenderson]

@ihhub Yep that makes more sense to me thanks for this. I'll update my PR.

[ihhub]

@matthewroberthenderson , thank you very much for your contribution to the project!

[matthewroberthenderson]

@matthewroberthenderson , thank you very much for your contribution to the project!

Very happy to. Really love this project, thanks for putting it out there.