Adding namespace support for the MapScript C# interface

[tamas]

According to the OSGeo affiliation the time has arrived to put the C# interface classes into the right place from a higher level of the abstraction. In this regard I'm planning to place the MapScript classes in a separate namespace so as to harmonize the project with GDAL/OGR where this change have already been done.

For choosing the proper name I should follow the general .NET namespace naming guildelines by using CompanyName.TechnologyName as the root. The names should be PascalCase-d without using underscores. Acronyms and abbreviations should also be PascalCase-d. As the result of this change the MapServer/GDAL/OGR classes will reside in the following namespaces:

OSGeo.MapServer OSGeo.GDAL OSGeo.OGR OSGeo.OSR

I will also change the module name from mapscript to MapScript at the C# interface since the classes should also be Pascal cased. However I will not alter the names of the remaining classes like mapObj since these classes come from a common ground of the SWIG bindings and should behave similarly for the various languages. We will also continue to maintain one reference document for all of the bindings.

[tamas]

The namespace support was applied in the trunk. r6274

The module name haven't been changed right now (remains 'mapserver') so as to keep the compatibility with the existing scripts.