Shock decomp

This pull request contains a number of bug fixes to the new plottting and realtime shock decompositions. All bug fix commits should also be cherry picked to 4.5 there is also a new option fast_realtime that should apply to options_.shock_decomp.fast_realtime for the realtime_shock_decomposition command.

Manually merged in master. Still needs to be added in 4.5 branch.

@stepan-a Needs to be combined with #1563

@JohannesPfeifer I saw, but I need to test first...

Cherry picked in 4.5 branch.