conversion would generate from the *.dj? files. Additionally,
it deletes the class files that would be generated. We can actually
delete all class files since the language level converter parses
the source files and thus knows what top level classes exist.
Also removed two log files that had been left in accidentally.
M src/edu/rice/cs/drjava/model/compiler/DefaultCompilerModel.java
M src/edu/rice/cs/drjava/project/ProjectProfile.java
M src/edu/rice/cs/drjava/ui/ProjectPropertiesFrame.java