Dpointer-build depends on requirejs-dplugins

[clmath]

When dpointer-build is used with decor-build, the requirejs-dplugins are already included in decor-build so the source version of requirejs-dplugins is not needed.

This could be fixed by building requirejs-dplugins in its own layer.

[wkeese]

A separate layer for dpointer sounds reasonable.

Although I think it would have been (and would be) better to combine decor and requirejs-dplugins. The distinction between the projects is artificial.