pyInterface: add calcIntegrals python script

add userInterface/calcIntegrals.py script. This script calculates an amplitude
integral matrix from all the amplitude files determined by the file manager.
Before executing calcIntegrals.py you need to first run calcAmplitudes.py with
the same fileManager.
For this change we had to introduce a new package function "calcIntegrals"
which takes a list of amplitude files as argument and returns the
ampIntegralMatrix object. The package function extracts all the amplitude trees
from the amplitude root files and adds the waveNames from the amplitude
metadata to the ampIntegralMatrix object (this is the new method 'addWave').
Then calcIntegrals calls the ampIntegralMatrix.integrate method, which has been
rewritten to take a vector of TTrees as argument (the tree extraction was
previously done in the ampIntegralMatrix object).
pyInterface: add script to compare amplitude files

add script that compares amplitude files for differences.
storageFormats: fix enumeration syntax for older compilers

Fix the enumeration syntax in convertEventFile.cc and eventMetadata.cc since
RootPwa didn't compile on older compilers.
amplitudeBenchmark not ready
General: Improve README.md

add short tutorial on how to use the new python user interface to README.md.
Improve layout of README.md in general.
pyInterface: add amplitudeBenchmark.py

add a script that runs a benchmark test if the result of the calcAmplitudes
script is consistent with the result of the script on a benchmark machine. Also
add a script that compares 2 amplitude files. The script will save 2 histograms
for the differences between the files, one for the real and one for the
imaginary parts.
pyInterface: add integralBenchmark.py

add a script that runs a benchmark test if the result of calcIntegrals script
is consistent with the result of the script on a benchmark machine. This
test ensures the precision of calcIntegrals on different machines.
config cleanup