decode() function in rasql

[Dimitar Misev]

In similar fashion to the rasql encode() function we could implement a decode() function for importing data by using GDAL.

Example for importing rgb for example:

rasql -q 'insert into rgb values decode($1, "png")' -f rgb.png ..

In this way we can deprecate most of the code in source:conversion as well as expand the capabilities to further formats that GDAL supports.