Merge pull request cs50#56 from cs50/globbing

fixes globbing

Merge pull request cs50#51 from cs50/remove-program_invocation_short_…

…name

removed program_invocation_short_name as unenlightening

replaces char * with string in the man pages

Merge pull request cs50#31 from cs50/size_t

size_t fixes

Merge branch 'codeship'

removed calls to free in non-get_string functions