Local File Path Updates

[lightcube]

A setting I would like to use more in Max is the Convert local paths to Relative global preference. However, there are known bugs with some of Max's functions when you turn this on. I propose these bugs (listed below) get fixed along with adding a new setting to accompany it.

1. FIX: Render to Texture won't work when you have this on. When you try to use RTT on a new scene with this on, you will get a file I/O error and the render fails.
2. FIX: The Send to Bitmap editor function in Slate is broken when the bitmap is using a relative path.
3. ADD: New option to go along with Convert local paths to Relative in preferences next to the option labeled "Only if Within Project". When on, the file path is relative if found within a subfolder of the project, otherwise use absolute path.

[lightcube]

Added Note: For the detection of local or not, the file should be considered local (and assigned relative path) even if it resides in a Symbolic Link that is in the project (ie., the file is actually not located in the project but a symbolic link makes it available inside the project folders).