wyuan; Add http://www.opensource.apple.com/source/gnutar/gnutar-413/tar/lib/strstr.c
wyuan; add an implementation from http://www.opensource.apple.com/source/gnutar/gnutar-413/tar/lib/strstr.c
wyuan; Add 'EXACT STRING MATCHING ALGORITHMS.pdf' from http://www-igm.univ-mlv.fr/~lecroq/string/index.html
wyuan; copy RaphaelJ's_fast_strstr from https://github.com/RaphaelJ/fast_strstr