Closes GH-305 Merge Linux and Windows recording plugins

- Merged the Windows desktop plugin into the Linux one
- The new plugin is simply named Desktop Source
GH-209 Create plugins for Windows for recording from USB/Webcam

- Uses dshowvideosrc to record on Windows.
Closes GH-209 USB plugin auto-detect devices

- Devices are now auto-detected using GstPropertyProbe on both linux and
  Windows Systems.
GH-209 Probe for device on linux

- Seems probing for device-name on Linux does not work as expected
Add "credits" and "license" to CLI intro message
Update copyright range
Allow for a clean CTRL+C exit in CLI
Closes GH-255 OggOutput plugin should allow user to disable matterhorn xml metadata
GH-179 Display free disk space in status bar

- Displays Free Space in the Freeseer status bar
Closes GH-107 Use hardware device strings rather than device nodes

- Linux Devices are now shown using their Device Names instead of the
  dev node.
Closes GH-301 Remove core from apps that don't need it

Core.py is no longer required. Tools should import core modules that they
need:

- config
- database
- logger
- multimedia
- plugin

Renamed some modules:

- QtDBConnector -> database
- gstreamer -> multimedia

Moved Core.DB functions to the database module
Moved Core.Backend functions to the multimedia module
Added settings module which stores useful global variables
CLI now only displays OS specific plugins

Closes GH-271 CLI should only show os-specifc plugins