Tendermint version (use tendermint version or git rev-parse --verify HEAD if installed from source):
./build/tendermint version
0.31.5-fd3445b3

ABCI app (name for built-in, URL for self-written if it's publicly available):

Environment:

• OS (e.g. from /etc/os-release):

Centos 7

• Install tools:
• Others:

What happened:
There are two problems.
1、Document is wrong
Reference https://github.com/tendermint/tendermint/blob/master/abci/example/kvstore/README.md.
Rule is "val:pubkey1/power1,addr2/power2,addr3/power3"

Isn't that the rule "val:pubkey1/power1,pubkey2/power2,pubkey3/power3"？

2、Operate failure
When I use app（PersistentKVStore） for operate validator set, need node pubkey which default use hex decode, but query validator pubkey by API (localhost:26657/validators) is base64 encode.

Read configure file(~/.tendermint/config/priv_validator_key.json) also use base64 encode.

When I want update validator voting power,but pubkey contains forward slash so that split result is wrong.
Example: curl -s 'localhost:26657/broadcast_tx_commit?tx="val:Vy3mgS0jodu/5zbs0dz99DYTgq/8vOHpFMsjxZSJtqw=/6"'

What you expected to happen:
Correct modify validator voting power and add validator by API.

Have you tried the latest version: yes/no
yes
How to reproduce it (as minimally and precisely as possible):

Logs (paste a small part showing an error (< 10 lines) or link a pastebin, gist, etc. containing more of the log file):

Config (you can paste only the changes you've made):

node command runtime flags:

/dump_consensus_state output for consensus bugs

Anything else we need to know:

My modify is "val:pubkey1!power1,pubkey2!power2,pubkey3!power3"

PR：#3641