The Makefile of the JuliaProcessor plugin used
absolute file paths, which prevented compilation.
I have replaced the absolute path with a shell
macro as suggested by Julia's embedding
documentation.

Fixing this revealed a second problem: the linker
flags were incorrect. I have replaced the
offedning flag '-ljulia' with build flags
generated by julia, as per Julia's embedding docs.

See issue #80

* Changed the order of plugin types at the enum definition.
* Changed some plugin definition names to be more user friendly and to
  be consistent with OE GUI.
* Removed "DataThread" plugin type from the "Plugin type" comboBox at
  the plugin creation page. Now to create DataThread plugin user
  should select "Processor" plugin type, then "Source" processor type
  and click "Use separate thread" button
* Removed possibility to create "Utility" processors plugins since we
  don't want to let users create such types of plugins.
* Removed possibility to generate editor and content component files
  for non-processor plugins since this feature was redundant.
* Removed "Plugin" page from "Config" for non-processor plugins since
  they have no built-in parameters.
* Added missing LookAndFeel related files to stage.
* Refactoring.

* Fixed OpenEphysLib files;
* RHD2000Thread class some refactoring and stylystic fixes.

* Created 3rd slider-page on creating project steps which is used
  to select appropriate plugin, processor type, plugin GUI template,
  other options.
* Created plugin GUI templates system;
* Created some plugin GUI templates for GenericEditor;
* ButtonGroupManager and TiledButtonGroupManager classes minor
  improvements and fixes;
* Changed index of ProcessorType::UtilityProcessor;
* Other minor bugs fixes.

* Added docs for the class. Override only buttonEvent (as for other non-visual editors)
* Started fixing other editors, a lot of redundant code can be removed.
* See comments in VisualEditor.cpp