add grab single todos.
modified:   grab.cpp: add comment for cleaning grab_single (that should be in wget class only).
add reduce code (WiP).
modified:   Makefile: upgrade version to v0.2.1.dev .
modified:   VERSION: version v0.2.1.dev .
modified:   grab.cpp: add reduce code for compution and display.
modified:   grab.help.output: auto-updated.
display both image and graph in live display.
modified:   grab.cpp: append image to graph in live display in reduce mode.
modified:   grab.help.output: auto-updated.
add reduce cycle for several graph display.
modified:   grab.cpp: setup several graphs for corresponding exposures in reduce live display mode.
modified:   grab.help.output: auto-updated.
add image tuning: 50% resize and 90 degree rotation.
modified: grab.cpp: add tuning for specific experiment.
modified: grab.help.output: auto-updated.
todo and comments
modified:   grab.cpp: todo cut, zoom; comment static part of the code: rotate and zoom.
modified:   grab.help.output
add next todos
modified:   grab.h: todo implement Ximea and V4L grab classes.
setup version v0.2.2
modified:   Makefile: upgrade version to v0.2.2 .
modified:   VERSION: version v0.2.2 .
modified:   _info.txt: add time stamp extraction example for Elphel.
modified:   grab.cpp: add more statistics on live display (i.e. min < mean < max).
modified:   grab.h: minor changes.
modified:   grab.help.output: auto-updated.