Configurable, optional arguments for mysqldump

# Changes

* Adds configurable, optional arguments for `mysqldump`
* Defaults to perform non-locking dump routine, assuming InnoDB is used
* Bumps Ruby to 1.9.3 (1.8.7 is end-of-life)
* The `mysqldump` binary path is collected from the database host, not localhost

# Testing

* Tested on Ubuntu 12.04 LTS 64-bit with MySQL 5.6.11