move variables to op-vars.el
define op-vars module
refine logic
fix typo
declare module op-enhance
improve parameter name
update category, add index/about
update compare-standard-date
update aggregation functions
fix a typo
add link blog/wiki to page header
show sign '>>' between date and title on index pages
update main file totally
rename org-page-util.el to op-util.el
refine op-util.el
rename depended module from org-page-util to op-util
merge newest code