added minPoolSize (#166)

Author: kyuan-mongodb

source/fundamentals/connection.txt

@@ -298,9 +298,15 @@ parameters of the connection URI to specify the behavior of the client.
      - Type
      - Description
 
+   * - **minPoolSize**
+     - integer
+     - Specifies the minimum number of connections that must exist at
+       any moment in a single connection pool.
+
    * - **maxPoolSize**
      - integer
-     - Specifies the maximum size of the connection pool.
+     - Specifies the maximum number of connections that a connection
+       pool may have at a given time.
 
    * - **waitQueueTimeoutMS**
      - integer