[vislib/tooltip] improve placement logic to consider viewport
[vislib/tooltip] more teasing, get sizing from a clone
[vislib/tooltip] tests
[vislib/tooltip] fix tests
[vislib/tooltip] the viewport does not always start at 0,0
[vislib/tooltip] generalize calculation of bounds
[vislib/tooltip] requery the DOM for tooltip el
save
Merge branch 'master' into tooltip_placement

Conflicts:
	src/kibana/components/vislib/lib/tooltip.js
[vislib/tooltip] move into the components
[vislib/tooltip] missed an old ref
Revert "save"

This reverts commit e275aa617af7a977cc3b947fafc6bef9e7ac7a0e.
[tooltip] increase test coverage with intergation tests, per @simianhacker
Merge pull request #1722 from spenceralger/tooltip_placement

Tooltip placement