4.0.6

Release for issues #34 , #35 and #36

Rev. 4.0.6 - 2016-03-08

Added: iBooksHelper
Added: CalibreHelper
Added: preliminary work for "Rendition" meta data
Added: dir attributes to the epub3toc (if writing direction is rtl)
Fixed: referenced links (url#id) broke on split chapters.
Fixed: Problem where chapter index name in the metadata could have the first chapter repeated. (#36)
Changed: Generated TOC file changed from using hardcoded spaces to indent nested chapters, to using the CSS, defaulting to 2em per level.
-    the tocCss can override this by defining .level[1-n], though the default only defines indents for levels 1-7.
-    reference links has their class as class=".level1 reference"
Updated: J. King's DrUUID library