Already okay in the CDK but needed fixing in BEAM.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Update beam to 0.7. Minor fixes to Kekulisation, reset Ring Numbering between components (fragments are now canonical C1CC1.C1CC1 instead of C1CC1.C2CC2).

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Avoid NPE due to implicit bond.

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