Update README.md

Mostly from the wiki page in project res, rest from https://wiki.openmrs.org/display/docs/Getting+Started+with+Reporting. Ticket: https://issues.openmrs.org/browse/GCI-13.
Merge pull request #87 from nfishman/patch-1

Update README.md
Merge branch 'master' of https://github.com/openmrs/openmrs-module-reporting