Add ST_CreateGrid function.
The function is based on a new signature and received two first arguments : a table name or a geometry.
Replace st_creategrid by makegrid and improve it
Fetch master
Enable NOCACHE option
Add st_makegridpoints to compute a regular set of points
cleanup
forgot to increment the cell index
Fix test and correct cell indexes
Add new tests and extract the commun GridRowSet.
The grid functions is able to work wih double::double delta X and Y
Add a new test with delatX!=deltaY
Update master
Fix import
Merge pull request #66 from ebocher/function/creategrid

Add ST_MakeGrid and ST_MakeGridPoints

With this PR, we add  the following create functions:

 * `ST_MakeGrid` replaces the `ST_CreateGrid` function
 * `ST_MakeGridPoints` replaces the  `ST_CreatePointsGrid` function

The signatures are

```mysql
ST_MakeGrid('tableName', deltax, deltay);
ST_MakeGrid((select the_geom from aSpatialTable), deltax, deltay);
```

Note:

1. The user cannot set an angle to rotate the grid because we consider that this job can be solved with a post SQL process.
2. The user cannot use a polygon mask to create the points only in a polygon. This operation will be done in the future using a specific function.

In order to simplify SQL spatial uses, new SFSUtilities have been added: 

* `getGeometryFields(ResultSet resultSet)`
* `hasGeometryField(ResultSet resultSet)`
* `getResultSetEnvelope(ResultSet resultSet)`
* `getResultSetEnvelope(ResultSet resultSet, String fieldName)`

See #41.