dependancy scan needs to be recursive

[damies13]

Describe the bug
From a discussion with, Nallavan G nallavan.qa@gmail.com:

So you understand what I think is happening, when you select the main .robot file the rfswarm GUI/Server scans the .robot file for and dependent files (Resource & Variable files) and includes them for transfer to the agent, but I don't think it then scans the dependent files for more dependent files.

To Reproduce
Steps to reproduce the behavior:

1. (File A) create .robot file with a dependent .robot resource file
2. (File B) create the .robot file that File A is dependent on, with another dependent .robot resource file
3. (File C) create the .robot file that File B is dependent on.
4. Select File A in rfswarm
5. Select test case from File A

Expected behavior
Files A, B & C should be downloaded to the agent machine