remove zIndex and table-cell support

- Remove zIndex = 999
- Remove table-cell support since it's not on the spec and not supported
by FF implementation
- Change temporary position to `relative` since it seems to be more
performant and remove old Opera check
add z-index test
edit readme
comment out the second table test
fix Stickyfill.stickies referencing the wrong (old) array in some cases
Merge remote-tracking branch 'origin/latest' into latest
fix receiving wrong viewport width in IE 9 and 10
merge new stuff into master