review-epubmaker: keep 1st stage temporary directory when debug is true.
Change Shift-JIS to Shift_JIS
Merge pull request #300 from suzuki/feature/change-charset-name

Change Shift-JIS to Shift_JIS
update Changelog
fix ID normalizing in @<bib>
epubmaker: support cover_linear in config.yml (from old review-epubmaker)

cf. doc/sample.yml
improved compatibility to GitHub flavored markdown
Merge pull request #303 from vvakame/update-markdown-builder

MarkdownBuilderがサポートする文法の追加
lib/review/htmlbuilder.rb, lib/review/idgxmlbuilder.rb:
provides warning message if image couldn't be found.