Skeleton change: read from stdin as per lab doc.

NB POSSIBLE AUTOGRADER BREAK

Lab doc told students to use
    ./a.out < testfile.txt
to run their code; however the program actually took in a filename on
stdin.

Modified the code to read its input from stdin. Other option was to
update the lab document, but this is easier & more amenable to
autograding- that said, the autograder is probably not yet set up to use
this input format.
Formatting of lab05 doc
Merge branch 'master' of https://github.com/aaronbloomfield/pdr
Removed unused variables from timer.cpp

Have, for several years, caused unnecessary warnings with -Wall.
Revert "Skeleton change: read from stdin as per lab doc."

This reverts commit 5f3fc716d873b0d98ee659b7bb90f904b1c4478b.

Change disapproved by Prof. B.
Merge pull request #19 from cceckman/master

Formatting and unused variables