Update TODO.txt

Author: jaehyunp

TODO.txt

@@ -2,4 +2,5 @@
 * Add fast Hadamard transform for solving the following problem:
     Given A[], B[], find C[] such that
       C[i] = sum_j A[j] B[i xor j]
-* Error-check the codes in stanford-cardinal-16 and merge them to the existing code base.
+* Error-check the codes in stanford-cardinal-16 and merge them to the existing code base.
+* Apostrophes in the title of a code file are translated as a accent in LaTeX; need to correct the behavior.