broadcasting fragments state in multiplex plugin (#394)
removed no longer required helper method
support for transition speed settings (closes #392)
simplified getCurrentFragmentIndex impl
Clarified documentation for multiplex plugin.

Thanks to @davidbanham for his help.
returning index only when current fragment is defined
fix prevents loading remote plugin several times when notes are enabled
hide rolling links backface
merge mutiplex fragment fix #395
increase min-height of cube/page transitions
Merge branch 'master' of https://github.com/ainformatico/reveal.js into dev
fix previous slide navigation logic (closes #397)
return current fragment index through getIndices, replaces getCurrentFragmentIndex #395
add a few more state background (#396)
correction to navigate top/right/bottom/left methods (closes #409)
Merge pull request #398 from jmdobry/multiplex-docs

Clarified documentation for multiplex plugin.
adjust order in readme
Added support for data-state in section when using external markdown files.
forward all attributes for markdown slides (#413)
more state backgrounds