[Proj] modified EPSG 28992 parameters

[bram van hoeve]

In the epsg-list included in Proj-4.6.0 the 'to wgs'-parameter is 
missing for the Dutch RD srs 28992. This causes a misprojection for 
reprojected 28992-files of about 13 meters East and 80 meters North. 
This issue effects among others FWTools-2.0.3 and above.
Meanwhile the problem can be solved by adding the parameter below to the 
appropriate place at <28992> in the current epsg file:
+towgs84=565.2369,50.0087,465.658,-0.406857330322398,0.350732676542563,-1.8703473836068,4.0812   


Kind regards,
Bram