test-lessons.sh: Stick with tabs for indenting the Bash code

Folks can set the tab-width in their editor to whatever indentation
depth they prefer ;).
test-lessons.sh: Use POSIX's 'command -v' instead of 'which'

'command' is in POSIX 2013 [1], but 'which' is not [2].  Sticking to
POSIX keeps us portable.

[1]: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/command.html
[2]: http://pubs.opengroup.org/onlinepubs/9699919799/idx/utilities.html
test-lessons.sh: Add '&&' before info() calls

We want the whole script to be one giant and-ed chain, so the script
will stop executing as soon as any command unexpectedly errors out.
test-lessons.sh: Fix '.:' -> '.' typo in student-workshop info string
test-lessons.sh: Condensed info messages

Try to keep the source under 80 columns, and avoid being too
distracting in the output ;).
test-lessons.sh: Less highlighting in info()

We want folks to focus on the info text, not the highlighting ;).
test-lessons.sh: Quote echo arguments

It's nice to explicitly say "this is a string we want to print"
instead of having the shell parse the string into arguments and then
have echo reassemble them into a string.  Plus many editors will give
you nice "this is not code" syntax highlighting for strings ;).
test-lessons.sh: Add .bowerrc files to repos with dependencies

Override the stock 'bower_components' [1].  After this, the
student-workshop tree output looks like:

  ├── README.md
  ├── bower.json
  ├── git-lesson
  │   ├── README.md
  │   └── bower.json
  └── shell-lesson
      ├── README.md
      └── bower.json

[1]: http://bower.io/docs/config/#directory
test-lessons.sh: Drop '-lesson' from dependency names

Collections will obviously be (by context) collections of lessons, so
'shell-lesson' is wordy.  With this commit, the script wraps up with
something like:

  ├── README.md
  ├── bower.json
  ├── git
  │   ├── README.md
  │   └── bower.json
  └── shell
      ├── README.md
      └── bower.json

  2 directories, 6 files
  bower check-new     Checking for new versions of the project dependencies..
  swc-workshop /tmp/student-workshop
  ├─┬ git#0.1.0
  │ └── shell#0.3.0 (0.2.0 available)
  └── shell#0.3.0
Merge pull request #6 from wking/test-lessons

test-lessons.sh: Assorted cleanups and a new .bowerrc