attribute and cleans up the naming of variables in
DefinitionsPane.java.
The following files were modified:
M src/edu/rice/cs/drjava/ui/MainFrame.java
M src/edu/rice/cs/drjava/ui/DefinitionsPane.java
M src/edu/rice/cs/util/ReaderWriterLockTest.java
M src/edu/rice/cs/util/ReaderWriterLock.java