Local Source and Output plugins
This is the Tx side equivalent of the Local Sink and Local Input plugins published in v4.6.0. Implements issue #338 More details in the respective readme's:
Other changes
Internal: single ChannelAPI interface. Preparation of v5. Implements issue #339. The most visible part is a change in the top banner of the channels on the left corner. The existing icon for basic channel settings has a "c" decorator inside and there is a new icon on its right with a "S". This icon will be clickable when the MIMO support is activated (v5) and open a dialog to set to which stream of the device to connect. For the time being as there are only single stream devices it is simply decorated with a "S" and not clickable. More details on this part in the section 6 of the main window readme