updated style
fix in lib_tw, was catching the wrong type of error
adding some tests for lib_tw

ess.lib_tw is broken due to removing star imports

SP_relativity and TTF added. They contain sets of functions to calculate beta, gamma and energy from each other and calculating the TTF and input phase for max energy gain in a field map.

A binary fieldmap batch conversion and trimming script is added. the conversion is now available also in TraceWin, but the rimming is still useful, specially if we add the other axes.