Created Xcode projects for all currently-built plugins.  Added Xcode workspace with "All" scheme for building GUI and all plugins.  Addressed some compiler warnings in plugin code.

On OS X, copy Rhythm-related files to the application bundle's Resources folder, and use the bundled copies at run time

Mac build fixes

Merge branch 'filereader_adjustments' of https://github.com/sept-en/plugin-GUI into sept-en-filereader_adjustments

* Adjusted positions for play, record, master clock components;
* Adjusted positions for CPU and Disk meter components;
* Stylystic fixes.

* Implemented sliders' material lookAndFeel;
* Material lookAndFeel have been applied to sliders;
* Improved UI layout for panel.
* Adjusted positioning of elements during resizing.
* New icon for "Mute" button;

FileReader: added possibility to drag&drop files. Refactoring and stylystic fixes. 

When double clicking on a channel to set fullscreen, the channel height
was set to 0 because the textbook wasn’t set to a correct selected
index. This now gets the value from the text, so it should work
regardless of how the value was entered.