add mask cropping.
modified:   PGlml.cpp: crop mask along both x and y (rectangle: x0,y0, x1,y1)
add mask scaling.
modified:   PGlml.cpp: add both crop and scaling example usage; add mask scaling (using mask=image size).
add croped and scaled mask output in an image file.
modified:   PGlml.cpp: add croped and scaled mask output in an image file.
upgrade version to v0.0.4 .
modified:   Makefile: upgrade version to v0.0.4 .
modified:   PGlml.cpp: small change.
new file:   PGlml.help.output: output of DGlml for command line options.
modified:   VERSION: version v0.0.4 .