Fix README

Author: Insoleet

README.md

@@ -9,15 +9,14 @@ A python implementation of [uCoin](https://github.com/ucoin-io/ucoin) API
  * uCoin signing key
 
 ## Requirements
- * Python >= 3.3
- * [aiohttp](https://pypi.python.org/pypi/aiohttp "aiohttp")
- * [asyncio](https://pypi.python.org/pypi/asyncio "asyncio")
+ * Python >= 3.5
+ * [aiohttp >= 0.19](https://pypi.python.org/pypi/aiohttp "aiohttp")
  * [pylibscrypt](https://pypi.python.org/pypi/pylibscrypt "pylibscrypt")
  * [libnacl](https://pypi.python.org/pypi/libnacl "libnacl")
  * [base58](https://pypi.python.org/pypi/base58 "base58")
 
 ##Installation
-You can install ucoin-python-api and all its dependencies via the following pip install :  
+You can install ucoin-python-api and all its dependencies via the following pip install :
 `pip install ucoinpy`
 
 Please take a look at the document [HTTP API](https://github.com/ucoin-io/ucoin/blob/master/doc/HTTP_API.md) to learn about the API.