The remove buttons are in the right-most column now as "X" icons,
and below the table (not scrolling) is a table-wide add button,
and depending on the settings, move up/down buttons. If moving
up and down is enabled, the column rows can also be moved using
drag and drop.
M src/edu/rice/cs/drjava/ui/config/VectorStringOptionComponent.java
M src/edu/rice/cs/drjava/ui/config/VectorAbsRelFileOptionComponent.java
M src/edu/rice/cs/drjava/ui/config/VectorKeyStrokeOptionComponent.java
M src/edu/rice/cs/drjava/ui/config/ConfigFrame.java
M src/edu/rice/cs/drjava/ui/config/VectorOptionComponent.java
M src/edu/rice/cs/drjava/ui/config/VectorFileOptionComponent.java
M src/edu/rice/cs/drjava/ui/ProjectPropertiesFrame.java