When distributing linear layout weights, also set size to 0dp

When distributing linear layout weights, also set size to 0dp

When you use the layout actions bar "Distribute Weights" in a
LinearLayout, in addition to setting all the weights to the same
nonzero value, also set the size (the height for a vertical linear
layout and the width for a horizontal one) to 0dp, to ensure that the
widgets are all given the same total size rather than sharing the
remaining space evenly.

In addition, when adding new widgets to a LinearLayout, see if all
elements in the linear layout already have nonzero and equal weights,
and if so duplicate this weight value on the new widget as well, and
similarly also duplicate 0dp/0dip/0px if used.

Change-Id: Iac5284a866b19b27e91666dc62278c63b8dde2bb