Change CO representation to SMILES='[C-]#[O+]', which is the true ground state.

We probably want resonance to the double bonded state later through charge resonance.
However [C+]#[O-] is completely wrong.
Consistency check for molecule adjlists by checking valency against p,u,c values.

Prior to this, the lone pairs were calculated using the given number of
radical electrons, and the charges were then set automatically with complete
disregard to user-specified charge.  Now, assume u and c to be implicitly zero
unless otherwise specified.  Therefore, if either u or c are nonzero,
they must be explicitly indicated or else they will fail the valency check.

We may want some group checks in the future.

Also includes fixes to unit tests to include these explicit charges and lone pairs.