implemented matio library for export MATLAB binary mat files (MUMPS, UMFPACK, PARALUTION)
DF_PLAIN_ASCII - removed lines with size and nzz (it should be loaded to MATLAB using "load matrix.dat; A = spconvert(matrix)")
DF_MATLAB_SPARSE - deleted
DF_MATLAB_MAT - MATLAB 5.0 format
DF_MATRIX_MARKET - not tested

http://sourceforge.net/projects/matio/
Merge pull request #113 from karban/devel

implemented matio library for export MATLAB binary mat files