Merge pull request bitcoin#1051 from pinheadmz/bip173-witnessversion1

BIP173: segwit address witness version is one 5-bit char not one byte

Author: kallewoof

bip-0173.mediawiki

@@ -208,7 +208,7 @@ be of the same length as the mainnet counterpart (to simplify
 implementations' assumptions about lengths), but still be visually
 distinct.</ref> for testnet.
 * The data-part values:
-** 1 byte: the witness version
+** 1 character (representing 5 bits of data): the witness version
 ** A conversion of the 2-to-40-byte witness program (as defined by [https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki BIP141]) to base32:
 *** Start with the bits of the witness program, most significant bit per byte first.
 *** Re-arrange those bits into groups of 5, and pad with zeroes at the end if needed.