Replace bootcamp with workshop

~~~
$ for file in $(grep -r -l 'bootcamp' .); do sed -i 's/bootcamp/workshop/g' $file; done
$ for file in $(grep -r -l 'boot camp' .); do sed -i 's/boot camp/workshop/g' $file; done
~~~

and others minors changes.

Close #240.
Merge pull request #742 from r-gaia-cs/replace-bootcamp-with-workshop

Replace bootcamp with workshop