Loading the raw data is slow

As several text files have to be read and parsed, this is rather time consuming.

See Loading of data for a more convienent way to work with EMC3 data.

import xemc3

%%time

ds = xemc3.load.all("../../example-data/emc3_example/")

CPU times: user 1min 1s, sys: 301 ms, total: 1min 1s
Wall time: 1min 2s