Changes made as of 9/21/2017
- updated all copy so that all "t"s in "The" are capitalized in The Opportunity Project
- corrected grammar of content on index.html
- added a link to The Opportunity Project Slack channel (https://join.slack.com/t/opportunity-data/shared_invite/MjM3MTQwNzI3MzE2LTE1MDQ3MTUxOTQtOTQ4YTQ3NjczOA) so people can join the Slack channel