Fixes some other third person camera specific attachments.
Implements a single new flag for entities to be forced visible in first person mode.
Old mods do not need to be updated to use the new flag and are fully backwards compatible.
This commit clarifies the maximal length of the serialized strings.
It will avoid accidental use of serializeString() when a larger string can be expected.
Removes unused Wide String serialization functions
Move LuaEntitySAO to a new dedicated file
Drop TestSAO (useless object)
Drop the old static startup initialized SAO factory, which was pretty useless.
This factory was using a std::map for 2 elements, now just use a simple condition owned by ServerEnvironment, which will be lightweight, that will also drop a one time useful test on each LuaEntitySAO creation. This should reduce server load on massive SAO creation
