MoCatalog: catalog based on mo streams

Read a mo file from a stream, and creates a dictionary-based
ResourceCatalog from it.
MoCatalog: Silverlight compatibility

use the other override of Encoding.GetString() to keep working on
silverlight(and other reduced profiles)
Catalog: move some files from the Tool

Move some files from the Tool project to the Catalog one, to avoid
namespace conflicts, fixes the Tests
MoCatalog: read context and gender

Read Context out of the .mo file, set the Gender and Context of the LocalizedString accordingly
MoCatalog: add license
Merge branch 'mo_catalog' of git://github.com/StephaneDelcroix/vernacular into StephaneDelcroix-mo_catalog