DOC: add new chapters
Update README
DOC: fix typo
DOC: fix typos
Ignore MANIFEST and any rst files in the root directory
DOC: change README.txt
DOC: improve intro
DOC: improve README
DOC: correct typo
DOC: improve intro
DOC: add new sections to Getting Started
DOC: new sections in getting started and improvements in tools
Merge branch 'master' into DOC_reorganize_user_guide
BUG-FIX: the hydrogenic xs were raising an exception when Z<13 and Z>36 because Egerton's original code was not designed to work out of this range
Add correction factor parameters for Na and Mg to the Hydrogenic XSs so that they better match HS XSs
Merge branch 'master' into DOC_reorganize_user_guide
EHN: axis='auto'
EHN: number_of parts and step_sizes = 'auto'
EHN: step_sizes=int
EHN: smaller dim