File paths for keynote files

[jessbhamra]

I know MC currently allows users to see file path locations for linked .rvt files, and the CTC Import & Link Manager shows locations of .dwg and image links and imports. It would be useful if MC could show the locations for keynote .txt files, wherever they were last located before they went missing. Also would be useful if a warning came up if a user is linking to a .txt file on their local machine or public parking. Related to issue #237 but for .txt links. Currently if Revit can't find the file, say it was on a user's local machine and they left the company for example, it just shows this:

[djsiroky]

Going to ping @gschleusner on this because it seems related to the idea of external resource server mentioned in #237. I think the changes Konrad is making will provide many of the pieces needed to implement something like this and provide regular expressions as paths that would trigger a warning to the user.

3 possible ways of implementing this, increasing in dev time but also control would be:

1. Try and retrieve the path when the situation in your image above occurs
2. Warn/stop the user when attempting to use a keynote file in a forbidden location (defined by MC)
3. Develop an external resource server that limits where external links (.txt, DWG, etc) can come from that is a reference to the project folder