Some formatting and flow changes:
* try to bring formatting of subheadings into consistency by promoting all bolded headings to hierarchichal headings
* add Paul Wilson as author
* initial directory changing and git checkout flow was not consistent with following commands
* added excercise around man pages and ls
* added comment on mental model of directory hierarchy
* labeled exercise at end of path section
* clarified conditions under which different ls commands were equivalent
*
A few more changes to be consistent and clear.
* q is for quit (mnemonics)
* tab completion seemed to have invalid examples/instructions
* made a table of less commands
* explained why less commands work in man
* redirection exercise was ambiguous: files that contain 4 in their contents, or whose names contain the number 4?
* mkdir is to 'make' a directory (mnemonics)
* combined sort exercise block
Can we get some documentation on tables
Seem to have the tables figured out - they need a header - annoying
remove some spaces getting in the way of bold
Updated data structures and variable / types

Revised these to match the output from the system to be used for the
practicals. Also added some stuff in on variable names.
Simplified hello.py and moved complex version to hello-extra.py

hello.py now only contains one command to print. The extra code is now
in a file called hello-extra.py
Merge branch 'update-shell' into 2013-04-uwmadison
There is no executable in the boot-camps directory - need to cd to shell dir first.
Merge branch 'update-shell' into 2013-04-uwmadison
Clean up ambiguity between file and filename.
Merge branch 'update-shell' into 2013-04-uwmadison
Fix old typo on file size.
Merge branch 'update-shell' into 2013-04-uwmadison
Add navigation and localize repo name
Update discussion of home directory to be user specific.
Need to change all pull paths to refer to a generic userspace if running on the same server.  This is a downside since running on a VM lets everyone have the same directory, just on different machines.
echo needs more characters for tab completion to work.  Removed ellipsis.
ls is aliases on this system and the results of 'which ls' will be confusing -switch to rm
Need to make user-specific directory in tmp since we are sharing a filespace.