The code generator was assuming all declarations for the current
file sit in the same namepace. Now uses the "on demand" namespace
switching we had for the forward declarations.

Also fixed a bug related to namespace lookup.

Change-Id: Ib54a3efbc752cbb9590302fa0707c0c73448db3d
Tested: on Linux.

Also included them in the C++ test.

Change-Id: Ib0c8470f0aacdf16616c27494abdda57a010195d
Tested: on Linux.

Fix to #360 - Updated the general generator (Java/C#) to emit fully qualified names where the referenced object isn't directly in this namespace. Added test fbs files to verify compilation.