Split customizer classes into individual files
Changed dirname to plugin_dir_path
Added empty() checks
Fixed a bug related to plugin deactivation

Upon switching to a non-Genesis theme, the plugin wasn’t deactivating
correctly and was throwing fatal errors. This fixes the error and adds
a notice that the plugin has been deactivated
Improved inline docs
Improved plugin file path definition
Added margin settings
Updated CSS for compatibility and margin settings
Merge branch 'Develop'