Improve error messages #69
Description
This report relates to the current V2.2.0-dev branch (f32b89c), while computing the "tree view".
When a command line program fails (comparison or distance computation), the error is only
visible under the "Show details" button, which most users probably don't access.
After the error, the rest of the computations just continue, leading to incorrect results for unclear reasons.
This problem happen often on systems that have little memory in relation to the number of CPU's.
The minimum expected error handling is a clear message, with instructions to reduce the number of CPU's if the error occurred due to "out of memory".