Add draft of bulleted feature summary

Most list points and some links are from the introduction to the Julia Manual http://docs.julialang.org/en/latest/manual/introduction/
Update download links to 0.2.0 final!
Merge pull request #67 from staticfloat/master

Update download links to 0.2.0 final!
Merge pull request #68 from ihnorton/master

Community: Add links to local Julia groups
Downloads page improvements
Merge pull request #70 from magistere/master

Downloads page improvements
Update description of uninstallation for Windows
Merge pull request #72 from magistere/master

Update description of uninstallation for Windows
Update index.md

We have 10.6 specific downloads now.
Add various GitHub organizations to the community page.
clearer, more concise github organization links & descriptions
Add links for subreddit and stackoverflow.
Merge branch 'master' of github.com:JuliaLang/julialang.github.com
Twitter tag.
Small updates to the community section.
Adds list of courses taught in Julia
Consolidate list of courses
Consolidate list of courses. Provides tutorials and articles.
Add Chicago meetup
Correct attribution to Western University Canada (sorry!)