Add some settings for cmake project generator on mac
[cmake] Removed superfluous mac stuff
Code formatting
Rearranging loops to improve performance
Renamed a function to make clear that values are overwritten
Reenabled neumann corrector (dunno why it was deactivated)
Whitespace and doc update
Added non-trivial boundary values to spe10
Simplified rhs assembly (all element parts are assembled in one place)

This makes the rhs assembly more costly as the coarse base function
set is evaluated more often. In turn, the assembly code is much
more readable. Also, this may make sense if the right hand side
function f has fluctuations on the small scale.