remove type and label from the extracted title.
add prefix 'rv' to internal ID for each converted files. Closes #204
review-epubmaker: support backcover
add hyphen to rv prefix
set 'noteref' style class for footnote referers. Closes: #205
Merge pull request #206 from takahashim/backcover

review-epubmaker: support backcover
use MathML::Symbol::CharacterReference; EPUB3 do not support EntityReference
review-epubmaker: support MathML in EPUB 3
review-epubmaker: strip HTML element in chapter items of TOC
HTMLBuilder: support epub:type="noteref" and epub:type="footnote" in EPUB3

cf: #205
split methods for test
simplizing code
yaml supports different section number level for PREDEF and POSTDEF
split review-epubmaker's core to library for test unit
copy stylesheet.
support hook and part.
support front/backmatter
refactoring, debug log, colophon.
update test for ePUBMaker.
Merge pull request #207 from kmuto/libepubmaker

merge epubmaker, revised review-epubmaker-ng as next version of review-epubmaker