update readme

Author: j2doll

README.md

@@ -1,12 +1,11 @@
 # json-downloader
 
 ## What is it?
-- OOO
+- Downloader using curl library.
 
 ## Requred Environment
 - Visual Studio 2017 x64
-- Windows 10 x64
-	- Maybe it will also build on Windows 7/8 x64.
+- Windows 10 x64 (Maybe it will also build on Windows 7/8 x64.)
 
 ## License
 - json-downloader is under GPL License 3. [https://github.com/j2doll/json-downloader](https://github.com/j2doll/json-downloader)