Fixed data type errors when filtering integer column with LIKE statement. Act II

You can reproduce this error with [Laravel-4-Bootstrap-Starter-Site](https://github.com/andrew13/Laravel-4-Bootstrap-Starter-Site) application when you filtering comments (http://localhost:8000/admin/comments)
Tested on MySQL, PostgreSQL, SQLite, MS SQL Server and Oracle (http://sqlfiddle.com/#!12/cd1eb/1/0)

My [previous pull request](https://github.com/bllim/laravel4-datatables-package/pull/23) was buggy with Oracle and PostgreSQL.
Checking each column meta info to get its max length is a bit overkill but it's the safer solution that I found.
Source: http://forums.laravel.io/viewtopic.php?pid=49058#p49058

Feel free to refactor or not my code.