MTIMESX - Fast Matrix Multiply with Multi-Dimensional Support

Fixed typos in the dsyrk, dsyr2k, ssyrk, and ssyr2k BLAS function prototypes. (These typo fixes should not change any results)

Added OpenMP support for custom code
Expanded sparse * single and sparse * nD support
Fixed (nD complex scalar)C * (nD array) bug

Added capability for nD scalar multiplies (i.e., 1x1xN * MxKxN).
Replaced the buggy mxRealloc API routine with custom code.
Updated mtimesx_test_nd.m file.

Fixed a bug for some of the (row vector) * (matrix) and (matrix transposed) * (column vector) operations in MATLAB mode that involved incorrect dimensions in the dgemv and sgemv calls.

Fixed a typo in the build routine for 64-bit systems, changed -largearraydims to -largeArrayDims

Added the multi-dimensional test routine mtimesx_test_nd.m for speed and equality tests. Added its description to the pdf file.

Fixed a bug for empty transa or transb inputs. Now treats these the same as 'N'. Also simplified the nD singleton expansion code a bit.

Added singleton expansion capability for multi-dimensional matrix multiplies.

Fixed bug in scalar multiply code that was causing incorrect results & crashes.

Fixed bug for (scalar) * (sparse) when the scalar contains an inf or NaN (in which case the zeros do not stay zero). Slight update to pdf doc.