Uodate README
Uodate README

* README: Add more information for building

* README: Add OpenMEEG in acknowledgements

* README: Add links to the forums and trackers on sourceforge

telehan/libmatio,MaartenBent/matio,CBL-ORION/matio,martinichka/matio-coder,CBL-ORION/matio,tbeu/matio,tbeu/matio,tbeu/matio,CBL-ORION/matio-sf-mirror,telehan/libmatio,tbeu/matio,MaartenBent/matio,CBL-ORION/matio-sf-mirror,NJannasch/matio,martinichka/matio-coder,martinichka/matio-coder,MaartenBent/matio,NJannasch/matio,MaartenBent/matio