avoid backward-compatibility broken introduced by #211. embed olnum attribute for automatic number instead of tweaking num attribute.
revert aefd92 due to #213. Closes #213
recommend to insert empty line before header
Fix error message more specifically. Ref #214.
Add description about catalog files. Ref #214.
review-epubmaker: fix EPUB3 support
review-pdfmaker: add contributors in colophon
Fix compiling HTML or LaTeX failed on emlistnum directive.
Merge pull request #217 from keiji/fix_emlistnum

Fix compiling HTML or LaTeX failed on emlistnum directive.
more test for topbuilder.
cover needs another ID for ePUB3
treat htmlversion/epubversion as integer
lib/epubmaker/epubv3.rb: remove and modify wrong meta definitions.
lib/epubmaker/producer.rb: add "modified" (YYYY-MM-DDTHH:MM:SSZ format) parameter for ePUB3.
fix parameters of PageMetric.new
fix error in travis with Ruby 1.8
fix test; use same ruby interpreter in test_*_cmd.rb
for debug