move saveCursor() and restoreCursor to DelegatingDocument
move FontManager and ColorConstants to package org.jboss.tools.aesh.ui.internal.util
rename document to delegate
rename currentStyleRange into currentStyle
move character constants out of AeshTextViewer, move reset() functionality to DelegatingDocument
remove unused proxy and currentStyle from DelegateDocument
move cursorOffset to DelegatingDocument
delete DelegateDocument class
rename DelegatingStyleRange into StyleImpl
rename DelegatingDocument into DocumentImpl
create and use TextWidget
rename package org.jboss.tools.aesh.ui.internal.widget into org.jboss.tools.aesh.ui.internal.viewer
extract and use VerifyKeyListenerImpl
extract en implement CursorListenerImpl
extract and use DocumentListenerImpl
rename AeshTextViewer into AbstractTextViewer