…s on disposal (#791)

* ParagraphText: immediately remove listeners from SelectionPath and Caret on dispose instead of waiting for GC (this improves PR #779, issue #627)

* ParagraphText: since weak listeners are no longer required for selection and caret listeners, remove listener classes again and move listener code to constructor (saves 100 lines of code)

* ParagraphText: MapChangeListener.Change.wasAdded() and wasRemoved() may both return true when replacing an item. So check both and handle wasRemoved() before wasAdded().

* Fixed (rare) NPE in class ParagraphText when GC frees object between two WeakReference.get() invocations

…the line contains custom objects (fixes #638)

Fix position of background, border and underline shapes in cases where the selection contains custom objects

Fixes #799 Alternate keyboard layouts not supported

* bug: getVisibleParagraph does not work with blank lines
* trim paragraphs using reference instead of object comparison (issues #777 and #788)

Add Astro IDE Project to RichTextFx Projects List

Added Astro IDE Project