Update all posts to the January classes' dates

I say "all posts" but it doesn't include notes...
Fix a build warning in atom.xml
Fix a deprecation warning in _config.yml
Update config.yml to say my name
[whitespace] Whitespace cleanup

trailing whitespace or whatever it was Sublime did automatically
Andrew-style curriculum for day 1
Remove the welcome slides

I don't think I'll use slides.
Fix formatting
more formatting fixes
Note pages to which I haven't yet attended
Merge pull request #1 from AndrewLorente/gh-pages

Teacher change, new dates, and Day 1 of curriculum