remove tags from instructions (IDGXMLBuilder.)
stop including chapter_postfix in chapter number.
replace literal doublewidth spaces in headers with chapter_postfix value.
Merge pull request #156 from tmtm/fix_header_reference

Fix header reference
sort out emlistnum in idgxmlbuilder.
escape href URL on IDGXMLBuilder.
make @<hd> hyperlink when --chapterlink is specified.
initial INAOBuilder implementation.
Add test for INAOBuilder
Break paragraph when encounting ===+
Merge branch 'master' into inaobuilder
Add tests for inaobuilder
Enable to output files in PART
Enable to use 'label' to identify inline_hd. Ref #116
fix #158  use us-ascii as literal encoding explicitly
Add description about inline_hd
Add number to POSTDEF files
Add require
Nil check
use own header handling for column-header instead of headline, to avoid misnumbering in HTMLBuilder.