a faster ring search to identify the atoms and bonds which are members of rings.

Conflicts:
	src/test/org/openscience/cdk/modulesuites/McoreTests.java

Change-Id: I044a11b41ad170dac31db0d541a2a9da63616f26
Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>