Fixes for datasources and multiple datasources.

Updated datasource urls as follows

http://mirrors.xbmcnightlybuilds.com/OpenELEC_DEV_BUILDS/
http://openelec.thestateofme.com/dev_builds/
http://snapshots.openelec.tv/

And made it check all 3 for the latest across them all

As iv done this on windows you may need to replace windows carriage returns as follows

sed -i $'s/\r$//' openelec-nightly_lite.sh