Insignificant comment and code style cleanup
updated `Picturefill JavaScript API` in index.html
residual version change
Skip non-`img` nodes when using `options.elements`

Prevent processing when `options.elements` contains non-`img` nodes.
fixed incorrect looping from length + 1 to length in parse descriptor, and removed unnecessary undefined check
Move picturefill length insert #340
Merge branch 'jonathantneal-move-length-insert'
Merge branch 'for_loop_plus_2_bug' of github.com:danieljsun/picturefill into danieljsun-for_loop_plus_2_bug
Merge branch 'danieljsun-for_loop_plus_2_bug'
Regen dist
Conflicts
Merge branch 'christophedejonge-contribute'