Remove redundant statistics from .db file

[fedarko]

This should be done towards the release of the tool, when we've more clearly defined the types of graphs that will be generated:

There's some redundancy in columns in the .db file. The main example I can think of is the use of both a node width and node height column, even though nodes are currently scaled by area (so width should equal height for all nodes). Update: we're looking into scaling differently right now (see #164), so this might be a moot point.

Once we've settled on a final specification for graph types, eliminate redundant stuff like this from the .db file. This will reduce .db size, which will in turn reduce processing time in the viewer.

[fedarko]

Also, "control point count" for edges might be removable.

[fedarko]

Also, the "shape" parameter for nodes is not necessarily needed, or at least is too much data -- we can easily deduce this info from the node id (is there a - prefix?) or have a "reverse_complement" parameter which just is either 0 or 1. No need to have "house" or "invhouse" |V| many times in the database.

[fedarko]

Update: yeah, width and height are now officially different due to a new scaling method (#175).

So the only real inefficiency I can think of at present in the .db files' schema is the use of the "shape" parameter, which could just be a simple boolean value for "isPositive"/"isForward" or something.

[fedarko]

This issue was moved to marbl/MetagenomeScope#30