bladeRF-cli: Can now specify multiple commands separated by semicolon

bladeRF-cli now supports multiple commands separated by semicolon, as requested in this issue https://github.com/Nuand/bladeRF/issues/345. If done in non-interactive mode, the command list has to be surrounded by quotes, ie. bladeRF-cli -e "probe;info" since bash also separates commands on semicolon.