Update for PureScript 0.15 (#49)

Complete 0.14 update

Fix unsafeEqThunk equality check (#34)

* unsafeEqThunk should call eqFn (a1/a2), not refEq

* eqFn is actually (b1/b2)

Merge pull request #33 from rnons/fix-has-attribute

Forgot to return in hasAttribute

Merge pull request #32 from rnons/remove-property

If a property is also an attribute, use removeAttribute

Merge pull request #31 from joneshf/fix-parse-error-for-0.13.x

Fix parse error for purs `0.13.x` on `v3.x.x` series

Merge pull request #27 from garyb/render-widget

Add "renderWidget"

Merge pull request #26 from slamdata/bump-fo

Bump purescript-foreign-object

Merge pull request #25 from garyb/mapthunk

Add 'mapThunk' for a combined hoist/map