Fix Matlab incompatibility of "ismatrix" (bug #42422). * data.cc (isvector): new tests * data.cc (isrow): documentation improved, new tests * data.cc (iscolumn): documentation improved, new tests * data.cc (ismatrix): is matrix now only checks the dimension due to Matlab compatibility, documentation improved, new tests * accumarray.m: use more appropriate function, than ismatrix * gradient.m: use more appropriate function, than ismatrix * num2str.m: use more appropriate functions, than ismatrix * ntsc2rgb.m: use more appropriate function, than ismatrix * condest.m: use more appropriate function, than ismatrix * expm.m: use more appropriate function, than ismatrix * onenormest.m: use more appropriate function, than ismatrix * isocolors.m: use more appropriate function, than ismatrix * isonormals.m: use more appropriate function, than ismatrix * isosurface.m: use more appropriate function, than ismatrix * __errcomm__.m: use more appropriate function, than ismatrix * __interp_cube__.m: use more appropriate function, than ismatrix * __marching_cube__.m: use more appropriate function, than ismatrix * __stem__.m: use more appropriate function, than ismatrix * stairs.m: use more appropriate function, than ismatrix * validsetargs.m: use more appropriate functions, than ismatrix * unique.m: use more appropriate functions, than ismatrix * bicg.m: additional tests for numerical value * bicgstab.m: additional tests for numerical value * cgs.m: additional tests for numerical value * gmres.m: additional tests for numerical value * qmr.m: additional tests for numerical value

--- a/scripts/linear-algebra/expm.m	Wed Feb 11 23:03:51 2015 -0800
+++ b/scripts/linear-algebra/expm.m	Thu Feb 12 18:34:56 2015 +0100
@@ -77,7 +77,7 @@
     print_usage ();
   endif
 
-  if (! ismatrix (A) || ! issquare (A))
+  if (! isnumeric (A) || ! issquare (A))
     error ("expm: A must be a square matrix");
   endif