Re-enable frame decorations since without them there is currently no way to move, resize or close the running application easily.
Fix layout to ensure that all components are visible and example icon tiles are rendered without horizontal scroll bar.

Some controls wehe stretching outside of visible area, for instance in the tree view.
Example tiles required horizontal scroll bar since VBox in which they were hosted was set to have too much width.
Layout was modified to properly fill the main stage window as is it is resized.
Generally removed any references to primary screen width, using dynamic sizing instead.
Upgrade ScalaFX dependency to latest milestone release.
Upgrade plugins and dependencies to latest releases.
Source code shown for the examples should come from the same code that is compiled to run the examples, to avoid discrepancy.

Deleted *.txt files containg the diplayed code and loading actual Ensamble code instead. This code still needs to be filtered to
change it into executable examples later. That is each sample shown to the user should extend JFXApp, so user can just copy and run it.
Add syntax highlighting to the displayed source code.
Modify code of the displayed source code, so it is in a form of a standalone ScalaFX application.

This is turning a code of a _class_ (that derives from EnsembleExample) into an _object_ (JFXApp). In some situations it may lead to initialization issues. For instance, is a variable is defined at the end of the class it may not be properly initialized in the app, resulting in NPE. That variable may need to be copied before `getContent` method (in the original code) or turned into a function (replace `var` with `def`). All examples need to be tested/inspected to ensure that they work after turning into an app.
Merge pull request #8 from jpsacha/master

Improvements to layout, syntax highlighting, and display of the source code