Fix integer values overflowing on signed INTEGER columns.

Doctrine does not hint or support unsigned schema columns, which means that by default columns will be signed in many DBMS - i.e. in MySQL this means that the max value for `INTEGER` column is 2147483647.
Fixed spelling error
Merge pull request #215 from leihog/patch-1

Fixed spelling error
Merge pull request #211 from Thinkscape/patch-1

Fix integer values overflowing on signed INTEGER columns.