Revamp Sinex parsing

Sinex file parser is not in line with other formats implementations. It still refers to DataLoader, it is a huge complicated class and is a nightmare to maintain. It mixes up Sinex and Sinex bias, which despite having a common base are different formats. It does not allow proper loading of OSB biases, it only handle DSB and probably mixes things up when parsing OSB or IFB files. It mixes the description within the data despite they are separated. Overall, it should be rewritten from the ground up.