fix: resolve coding for json

release: v0.4.1

-  fix: 修复python2.7下RSAEncrypt的plaintext参数编码
-  feat: 新增RSADecrypt参数sentinel
-  docs: 更新js和api说明

fix & feat: set aes output/input format, support hex and base64

update setup.py longdoc

update .travis.yml

v0.2.1 fix sign bug

v0.1.0 release