add: what to include in Additional Information
upd: new nidm componets figure
upd: spell out accronyms
fix: preprocessing now workflow
fix: NIDASH replaced with NIDM
upd: use the new nidm-overview figure
rm: use the old nidm-organization figure
upd: set image width to 800
upd: text to relfect new figure
add: workflow sections
add: niquery api sections
rm: old nidm overview fig
add: details to figure 1
fix: clarify not just MRI
fix: update intoduction details and add data modelers
fix:  nidm-results url
add: table to additional info section
fix: harmonize table layouts
fix: typos and details
Merge pull request #74 from nicholsn/specs/nidm-overview

MRG: NIDM Overview - Ready for Review