spatialite api - gaiaTransform

[mj10777]

I ran into a problem, while attempting to add a 'cutline' logic for RasterLite2-RL2_WriteGeoTiff (and others)

- the first results looking good, but very slow

At first I added direct 'gaiaGeomCollPtr' logic to analyse the given cutline

- which I will replace since it does not seem a good idea to mix them both together

I noticed, when checking that the cutline srid is not the same a the raster_coverage srid 

- I could not use the public 'gaiaTransform' function, since the 2 proj4 parameters

-- need the private function 'getProjParamsEx' to fill these parameters

So maybe a version of 'gaiaTransform' should be offered as public

- accepting 2 integer values 'i_srid_from', 'i_srid_to'

-- calling the private function 'getProjParamsEx' as needed

Mark