Merge pull request #43 from ercchy/gh-pages

Adding events in calendar to  the landing page
Update 2000-01-01-concepts.markdown

Text edits
Update 2000-01-01-introduction.markdown

Text updates
Update 2000-01-02-github-cheatsheet.markdown
Update 2000-01-02-markdown-cheatsheet.markdown
Update 2000-01-03-glossary.markdown

Text updates, added links
Merge remote-tracking branch 'upstream/gh-pages' into gh-pages