Vertical statements should automatically add intrinsic-height constraints where necessary

[paulyoung]

Currently the following statement:

@v [#platform-h2]-[#platform-h1]-[#platform-first-p]-[#platform-second-p]

only works if these constraints are also added:

#platform-h2[height] == #platform-h2[intrinsic-height];
#platform-h1[height] == #platform-h1[intrinsic-height];
#platform-first-p[height] == #platform-first-p[intrinsic-height];

Instead, [intrinsic-height] could be automatically added for all but the last item.

[paulyoung]

Similarly, this example only works by manually adding intrinsic-height:

@v [#platform-second-p]-| outer-gap([margin] * 3) in(#platform);
#platform-second-p[height] == #platform-second-p[intrinsic-height];