More improvements to dot output
More improvements to dot output

-Disable column types by default
-Ignore columns with name "id"
-Single rectangle shape for tables w/ only an "id" column (location subtypes)
-Add font, fontsize to the entire graph
-Remove font/fontsize from individual node/edge definitions (less clutter)
-Change the arrowhead/arrowtail images
-Use .title() instead of .capitolize() for table name strings

Reviewed-By: Wesley Hertlein <ca32100e9f664971b15d1470ddc7f009d907efd3@morganstanley.com>

quattor/aquilon,quattor/aquilon,guillaume-philippon/aquilon,guillaume-philippon/aquilon,stdweird/aquilon,stdweird/aquilon,guillaume-philippon/aquilon,quattor/aquilon,stdweird/aquilon