Add SPOJ Solutions

[gopalgoel19]

If you have solutions to problems not already in the repo, add your solution.
Must follow the guidelines mentioned in the README file.

Added SPOJ solutions for few graph and adhoc problems here: #20

[jonathandrnd]

New SPOJ Solutions, here: #28
QTREE2: Lowest Common Ancestor
HORRRIBLE: Binary indexed Trees
BOMBER: Grundy Numbers
GSS5: Segment Trees
MUTDNA: Dynamic programming
TOURIST: Dynamic programming
AGGRCOW: Binary search
AMR10C: Theory numbers

[aptrishu]

Can you please assign me this issue?
Thanks.