Support Tomcat JDBC Pool

Support [Tomcat JDBC Pool](http://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html).

Sample to use Tomcat JDBC Pool instead of the old style DBCP Datasource:

```
bees app:bind -a MY_APP -db MY_DB -as mydb factory=org.apache.tomcat.jdbc.pool.DataSourceFactory
```

* `-a`: name of the application
* `-db`: database name
* `-as`: alias which is used to build the JNDI name (in the sample `jdbc/mydb`)
* `factory=org.apache.tomcat.jdbc.pool.DataSourceFactory`: specify `factory` attribute as described in [How to use JDBC Pool > Inside the Apache Tomcat Container](http://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html#Inside_the_Apache_Tomcat_Container)