fix broken link in README.md
fix broken link in README.md

')' character is missing.

Additionally, Github's Markdown does't handling URL containing parentheses ``()``, so use alt link format.

ref. http://meta.stackoverflow.com/questions/13501/links-to-urls-containing-parentheses
Kirow/jsonlite,amamchur/jsonlite,kleemedia/jsonlite,kleemedia/jsonlite,Kirow/jsonlite,amamchur/jsonlite,kleemedia/jsonlite