open file in read mode only
fix Ruby 1.9 version match
resolves #737 disable subs on pass block by default
Merge pull request #746 from mojavelinux/issue-737

resolves #737 disable subs on pass block by default
resolves #745 push_include and pop_include should return nil
Merge pull request #747 from mojavelinux/issue-745

resolves #745 push_include and pop_include should return nil
resolves #639 emit warning if tag(s) not found in include file
Merge pull request #748 from mojavelinux/issue-639

resolves #639 emit warning if tag(s) not found in include file
reduce indexterm macros to one regexp & simplify it
resolves #531 added support for anchor:<id>[<reftext>] macro
Merge pull request #753 from mojavelinux/issue-531

resolves #531 added support for anchor:<id>[<reftext>] macro
resolves #624 moved all compliance flags to Compliance module
Merge pull request #755 from mojavelinux/issue-624

resolves #624 moved all compliance flags to Compliance module
resolves #492 added math blocks & inline macros, integrated with MathJax
resolves #760 added math style & macro name to use default math engine

- 'math' attribute activates math
- default value of 'math' attribute is 'asciimath'
- use DOMContentLoaded hook to load MathJax
- define constant for math delimiters
change AsciiMath delimiter from ` to \$
Merge pull request #757 from mojavelinux/issue-492

resolves #492 added math blocks & inline macros, integrated with MathJax
resolves #763 added scaling & alignment attributes to block image in DocBook backend
add % to scaledwidth if no units given
Merge pull request #765 from mojavelinux/issue-763

resolves #763 added scaling & align attributes to block image in DocBook backend