Fixed warnings from NetBeans (use of generics, final fields, ...).
Added Preview tab in editor (MultiViewElement).
Changed highlighter to use EMPH/STRONG token IDs instead of ITALIC/BOLD.
Removed unused token IDs ITALIC/BOLD.
Fixed highlighter to use EXPLINK for inline links (was EXPIMAGE).
Fixed highlighter to use VERBATIM for verbatim blocks instead  of BLOCKQUOTE.
Extended Markdown example file and registered it for use in the Fonts & Colors section of the NetBeans options window.
Fixed references to localizing bundle in layer file and added missing entries to bundle.
Changed initial content of Markdown preview tab to empty document.
Updated PegDown library to version 1.4.1.
Bumped plugin version to 1.4.
Added separate tokens for header levels 1 to 6.
Added base types in Font & Color settings for links, images and headers.
Added Parser and StructureScanner implementations to provide Navigator view and bread crumbs.
Added folding support.
Fixed navigation via bread crumbs, however "Go To Source" in the Navigator is still broken.
Fixed navigation via Navigator, but broke navigation via bread crumbs. No idea how to get both working at the same time.
Added root item for Contents in Navigator.
Added References to Navigator.
Added Abbreviations to Navigator if the corresponding extension is enabled.
Added copyright notice to license.
Added plugin description for preview release.
Updated project readme file.
Added screenshots to project readme file.
Merge #29 Integration of fork
Merge #29 Integration of fork