Add more tests to ensure correct alignment values

The tests ensure any change in the behaviour of qstart, qend, sstart,
and send is reflected according to any changes made in future BLAST.
There a slight inconsistency between blastn and other methods about
the way they are shown. blastn automatically swaps the start and end
coordinates according to frame values while for others it has to be
inferred.

Signed-off-by: Vivek Rai <vivekraiiitkgp@gmail.com>
Move formatter functions to Report#, changes to filter_hsp_stats

The helper functions for printing HSPs are now part of Report class
instead of HSP. filter_hsp_stats() now uses string interpolation.

Signed-off-by: Vivek Rai <vivekraiiitkgp@gmail.com>
Added comment explaining blastn result inconsistency

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