Switch to latest Sinatra.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Slightly refactor Blast::Hit.

* Blast::Hit#total_score -> Blast::Hit#score.
* Blast::Hit#def returns empty string if 'No definition line'.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Slight refactoring of Blast#HSP.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>