Fix #653 Dialog not hidden on desktop region selection
Fix #663 Selecting a desktop record region does not always work
Fix #650: Resetting configuration raises error when file do not exist
Fix #627 Clear text fields when removing a talk or removing all talks
Fix #664 Feedback when desktop record region selected
Skip tests related to RTMP plugin for Windows

The RTMP plugin is not included in GStreamer for Win32, so the test based on it will fail on Windows.
The workaround is to skip the RTMP test on Windows.
Updates to http errors, and validation

Changed HTTPError class to have more standard error messages, and
custom inner descriptions.

Decoupled JSON Schemas from validate module, now schemas are either
generated by config classes, or stored statically in the api blueprint.

Added JSON validation schemas to recording api Blueprint

Updated validation tests for validate.py changes, changed xunit setups
to pytest fixtures