update training and checkout process
update training and checkout process

- Removes reference to Fall 2016 open instructor training. 
- Removes reference to Data Carpentry specific checkout process.
datacarpentry/datacarpentry.github.io,datacarpentry/datacarpentry.github.io,tracykteal/datacarpentry.github.io,tracykteal/datacarpentry.github.io,ErinBecker/datacarpentry.github.io,tracykteal/datacarpentry.github.io,ErinBecker/datacarpentry.github.io,datacarpentry/datacarpentry.github.io,ErinBecker/datacarpentry.github.io,tracykteal/datacarpentry.github.io,ErinBecker/datacarpentry.github.io