Add missing jgoodies-common dependency

Recent versions of JGoodies Forms depend upon a corresponding version of
JGoodies Common; in the case of Forms 1.7.2, this is Common 1.7.0.  The
build will pass and no exception will be thrown if JGoodies Common is
missing, but anything relying upon JGoodies Forms (e.g. the Bio-Formats
ImageJ plugin) will silently fail to display the relevant window(s).

This was introduced by the upgrade from JGoodies Forms 1.3.0 to 1.7.2
in 0edcf7e8f5253821733cfe763e89b43a8cd1f965 (i.e. gh-951).

To test, verify that with origin/dev_5_0, attempting to open a file with the Bio-Formats ImageJ plugin does not move beyond the file selection stage (the import options window should not appear).  With this PR included, the plugin should behave as usual.