The load_dbc method fails if the DBC file has non-native line endings

[RobPearce]

Running PyUSBTin on Linux but with a DBC file written by a Windows program (Kvaser DB Editor) results in only the first frame (message) being loaded but all the defined signals being allocated to it. I'd provide a patch but the "parser" uses regex's - which is a really bad idea nearly all the time - so it's rather hard to figure out how to fix it.