Output format of electric field with DBG_SCALARFIELD=TRUE

When enabling DBG_SCALARFIELD=TRUE OPAL prints the scalar and vector fields to files. In case of a vector field the brackets and commas a written, making it unnecessarily difficult to parse with Python. An example is the electric field with following output format:

x y z ( Ex , Ey , Ez )

I discussed it with @winklehner_d and he okayed to change it.