update and improve op-template.el
update op-vars.el, add new variables
update org file export mechanism, make it compatiable with org v8.0
update dependency
update template, using mustache.el as templating engine instead of simple format-spec
fix html quoting issue: org v8.0 has changed the syntax
fix html tag issue: mustache will transform html tag by default, use {{{}}} to escape
[#61] remove meta info section on irrelevant pages
update creation date display format
fix uri generation issue caused by date format