[subgridlist] communicate coarse grid boundaries
[subgridlist] use correct number of fine cells on coarse boundary elements
fixed two typos
[localSolProxy] removed unused argument

This was given runtime errors in parallel runs
as subgrid_list.gridPart(0) does not exist on
all processes but only on one.
[gridCreation] cleanup
[gridCreation] compute necessary number of overlap layers for coarse grid
[msfemSolver] use id instead of index in output

This makes debugging a lot easier in parallel.