Made it easier to customize UI colors

...yCode/src/gui/components/lookandfeel/juce_LookAndFeel.cpp

Source/AccessClass.cpp

Source/Processors/Editors/GenericEditor.cpp

Source/Processors/Editors/GenericEditor.h

Source/Processors/Editors/LfpDisplayEditor.cpp

Source/Processors/Editors/SpikeDisplayEditor.cpp

Source/Processors/Editors/VisualizerEditor.cpp

Source/Processors/Editors/VisualizerEditor.h

Source/Processors/GenericProcessor.cpp

Source/Processors/GenericProcessor.h

Source/Processors/Parameter.cpp

Source/Processors/Parameter.h

Source/Processors/SignalGenerator.cpp

Source/Processors/Visualization/SpikeDisplayCanvas.h

Source/UI/CustomLookAndFeel.cpp

Source/UI/EditorViewport.cpp

Source/UI/ProcessorList.cpp

Source/UI/ProcessorList.h