- relation support
- completed and refactored lua script builder

- http://redis.io/commands/eval
- http://www.lua.org/

fixes #854

copied from
https://github.com/CUBRID/node-cubrid/blob/056e734ce36bb3fd25f100c983beb3947e899c1c/.travis.yml

fixed expected quoting

Reverted 0bf2dadd: it's very common to use lower case for column types and upper case for other DB keywords.

http://jira.cubrid.org/browse/APIS-658

bit has special syntax for storing and retreiving so we'd need a
converter for that.
Storing 1 bit will result in one byte left padded on the disc so the
result of a query for boolean 0 will be 0x00 and for boolean 1 will be
0x80.

- rename FileHelper::mkdir for API consistency
- changed default permission for directories to 775 instead of 777
- added some properties to classes that deal with files to allow control
  over directory permissions.