Update README.md

CHG: Some hyper-links have been changed.

git-svn-id: https://php-sql-parser.googlecode.com/svn/trunk@1245 44dcfd11-89b7-3d55-2063-5c365055f77f
ADD: a submodule for the GitHub wiki

git-svn-id: https://php-sql-parser.googlecode.com/svn/trunk@1246 44dcfd11-89b7-3d55-2063-5c365055f77f
ADD: the new Wiki pages from GitHub
ADD: the wiki pages from GitHub

git-svn-id: https://php-sql-parser.googlecode.com/svn/trunk@1247 44dcfd11-89b7-3d55-2063-5c365055f77f
Merge branch 'svnsync'