Change to narginchk.

Updating the check for number of inputs, as the previous method is to
be discontinued in future versions of Matlab.
irf: if irbem not working suggest mexopts.sh update for mac
Merge branch 'master' of github.com:irfu/irfu-matlab
Improved error message
Changed cfa -> csa.
Fix for C3 probe 420
Format fixup
Merge branch 'master' into devel
added plots/Example_CSA that creates figures seen on CSA AIO web page data section