added mysql update feature
tests added , missing errors handled
de duplication of build where and set
Added an iterable array of non-empty values to 'Enums'.

Resolves pull request #52.

Added members as per request. Kind of completely unnecessary.
You can do 
``` javascript
var AnEnum = EnumFactory('dog', 'cat', 'mouse');
for(var i in AnEnum){ console.log(i) }
// DOG
// CAT
// MOUSE
```
Update README.md
Merge pull request #54 from jbrick/master

Update README.md
re-run travis
Merge branch 'master' of git://github.com/jugglingdb/mysql-adapter

Conflicts:
	lib/mysql.js
code rebase
added update test to coffee
Merge pull request #44 from pasindud/master

added support for mysql update queries
Adding support for length option for string data types