Use naming convention for gdal plugin source files

[artemp]

From the dev list:

DataSource is an OGR naming convention whereas Dataset is used for GDAL.

https://lists.berlios.de/pipermail/mapnik-devel/2008-September/000731.html

Consideration should be given to correcting these files to better fit gdal convensions.

[artemp]

[kunitoki] I think we should keep a naming format specific to mapnik datasources, not following the underlying driver implementation naming convention (we will end up mixing too much in all drivers implementation).

If we choose that a '''dataset''' is our source of information, then we should use that in every driver. It is much more straight forward to remember (as i don't have to remember each driver naming convention) and is less error prone (by mixing wrong names in different datasource configuration).

We only need to choose which is the right name for a ''source of mapping informations'' !

[artemp]

[springmeyer] okay, that good reasoning. 'datasource' would conflict with mapnik.Datasource...

So, I guess renaming file-> dataset for both the gdal and ogr driver would be what we should put on the table for consideration.