Clang format run on near-the-header lines.

Happy New Year

This has some follow-up changes.

Don't repeat typename in emplace_back.

Mainly the shape matrices are affected.

Creating integration method object for every assembly
is not cheap because of the std::pow call. Since the
method does not change, it can be stored once per
assembler.

This is only used in local assembler implementation.
Clarifies content of that file.

This slightly reduces included amount of code.

Creation of local assemblers belongs to the processes.