Rename `MyConn` -> `MyInnerConn`
Move `QueryResult::next` to `MyInnerConn` impl
Merge branch 'master' of https://github.com/blackbeam/rust-mysql-simple

Conflicts:
	conn.rs
	pool.rs
Treat zero pool cap as an infinite
Move `MyConn::query` and `MyConn::prepare` to `MyConn::_query` and `MyConn::_prepare`
Move `MyConn::execute` to `MyConn::_execute`
Make `MyPooledConn::query` and `MyPooledConn::prepare` public