Update GRADES.md

Under the instructions to use the `scripts/calcgrade.sh` script to check our overall grade, I changed: "The `calcgrade.sh` script expects a single argument that corresponds to the github account of the grade you want to check." to "The `calcgrade.sh` script expects a single argument that corresponds to the github account of the grade you want to check." 

I thought this would be clearer since appending my github account didn't work for me but my ucr netid/cs account did, and based on what the instructors said in issue #303.
Update ls.cpp

The missing semi-colon generated two compiler time errors.
Merge pull request #306 from aorti017/patch-1

Update ls.cpp
Merge pull request #305 from gbrlrz017/cs100-2014fall

Update GRADES.md
fixed link in README.md

fixed a typo in README.md

fixed typo in README.md
Merge pull request #308 from jstod001/cs100-2014fall

RE: Fixed typos in various README.md files
One bug is not by ls for ls -a
lecture notes
Merge branch 'cs100-2014fall' of https://github.com/mikeizbicki/ucr-cs100 into cs100-2014fall
fixed minor typo
edited calcgrade.sh so unverified signatures don't show as "bad signature" and instead say "signed but untrusted". Students aren't likely to have a web of trust that includes the instructors.
added a function that will check if a key already exists in repository
Adds signing key to repository if it does not already exist
addgrader.sh will now append new keys instead of overwriting
Update README.md
Update README.md
Merge pull request #318 from Liniarc/new

Students can now see signed commits. Fixed typo in config.sh
Update README.md
added check for Instructor Keys
added check for gpg