Added instructions to avoid MySQL Error 2002 

It is sometimes required to specifically mention the start of the mysql server to avoid the following error
```
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
```
Updated error resources for ValueError for Mac OS X, Fixes #18
Merge pull request #17 from sudheesh001/master

Added instructions to avoid MySQL Error 2002