[geotk] Better documentation of map projection parameters

[Martin Desruisseaux]

Hello all

With the addition of NetCDF and Proj.4 map projection parameter names, we have 
feel the need for a cleanup and better documentation of supported names. The 
result is a table summarizing all names known to Geotk:

http://www.geotoolkit.org/modules/referencing/operation-parameters.html

In addition, the following package javadoc:

http://www.geotoolkit.org/apidocs/org/geotoolkit/referencing/operation/provider/package-summary.html

has been completed with the following information in every provider class:

   * A summary of parameter names in the class javadoc.
   * More detailed parameter information in the javadoc of the PARAMETERS field.
   * When available, the geographic area were the projection appears to be used.

Those information are generated automatically, so the should stay up-to-date 
with future versions of EPSG database and Geotk.

     Martin