Add ability to use AS statement in queries

This will add the ability to do an AS statement in your queries and not break the result
e.g. 

$result = DB::table(str_plural($this->model))->where('account_id', '=', 333)->select('id', 'title', DB::raw("LEFT(contents, 40) AS contents"));
return Datatables::of($result)->make();
version update
omitting version field
Cast columns only for PostgreSQL when filtering.
Merge pull request #36 from tortuetorche/patch-1

When filtering, cast columns only for PostgreSQL.
Merge pull request #33 from Clooner/patch-1

Add ability to use AS statement in queries
Update Datatables.php
with() not needed unless method chaining
Pass the Model object to the callback function instead of the row array

This does not break old code because the Model object implements ArrayableInterface. We can still access the callback with

    function($m) { return $m['id']; }

as well as

    function($m) { return $m->id'; }

Now though, we can access modified attributes from Eloquent getters as well as relations on each model. A nice easy change without breaking backwards compatibility. :-)
Columns' is used by DataTables only for reordering columns (by name) not my column number you are setting in javascript
Fixed row count when selects have group by in them

When using data-tables with a query that has a groupBy statement the count returns a number that is related to the count of the group instead of the count of the entire rows. This causes the pagination to be inacurate
Merge pull request #52 from MarkVaughn/patch-1

Fixed row count when selects have group by in them
Merge pull request #47 from umefarooq/master

sColumns in json output from server to show added columns
Merge pull request #44 from ChrisReid/patch-2

Pass the Model object to the callback function instead of the row array
Merge pull request #43 from ChrisReid/patch-1

with() not needed unless method chaining.
Added clean columns function
Fixing error introduced by last patch where bindings were lost

Like mentioned in issue #53 the new count function loses bindings causing a sql error. this patch fixes that.
Merge pull request #55 from MarkVaughn/patch-2

Fixing error introduced by last patch where bindings were lost
Count prefilter and post filter

To comply with datatables iTotalRecords & iTotalDisplayRecords
#32 #27
reintroducing eloquent/fluent check