ManagedRawFileWorkspace2D checks the speed of data input from the raw file. If...

ManagedRawFileWorkspace2D checks the speed of data input from the raw file. If it's too slow because the file is on a network disk a cache file on the local drive can be created. A new property called "Cache" is added to LoadRaw2 algorithm. It takes values "If slow", "Always" and "Never" which mean create cache if connection is slow, create anyway or don't create in any case. re #304