Add uri_str_to_bytes(), byte_array_dup(), and byte_array_equal()

Add uri_str_to_bytes(), byte_array_dup(), and byte_array_equal()
functions to strutil.  Use GByteArrays to store SSIDs for decryption,
and let the user specify arbitrary byte strings using percent-encoded
strings.  We should probably add percent encoding for pass phrases as
well, so you can escape the ":" character.

Move the key struct key conversion utilities to airpdcap.c, and remove
duplicate code from packet-ieee80211.c.  Fix a lot of indentation.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@20388 f5534014-38df-0310-8fa8-9805f1628bb7