Partially added data-attrib enabled graph display

The commit intends to implement the Graph display for multiple hits and
alignments using data-attribs which are then used by the client-side JS
to render the graph. I haven't removed the original code YET as there
are some bugs. Particularly, ther scale doesn't appear for few of the
hits in the result. Those will be addressed in next commit perhaps.

Signed-off-by: Vivek Rai <vivekraiiitkgp@gmail.com>