** Structures for scoring
new_score_mat () will just make an empty score matrix
score_xxx () will add in the score due to the xxx
contribution.
This makes it easy to add in secondary structure, sequence
info, force field scores and so on. It no longer treats
secondary structure as a privileged data type.
* iteration
This can perhaps be done at the perl level
Do an initial alignment in the residue non-specific force
field, followed by a scoring using the residues actually
present.

* Scoring

** f7
Adapt to handle profiles.
*** speedups
**** precalculate and store phi psi's with templates
**** precalculate structural class for each site

* Variables
Things like gap_open and gap_extend should be passed as
parameters into the alignment. There is no need to have them
as persistent variables.

* Alignment Code

Introduce general, position-specific gap penalties.
These would usually come from secondary structure (gap costs
10 times as much in a recognised secondary structure).

* Profiles
** structures

Create profiles as a top level data type.

** sequence sequence
Modify code so as to handle fractional residues.
Write with and without site specific gap penalties.