Resource layout

[louis-langholtz]

Expected/Desired Behavior or Experience:

The file-system organization matches the declared names and their namespaces, and their depths match what users need.

For example, users don't need to access WorldImpl.hpp as much as they need to access World.hpp so WorldImpl should be in a deeper, more implementation oriented namespace, than World. Subsequently, the WorldImpl.hpp file should be in a sub-directory of the directory in which the World.hpp file is within.

From a code perspective, this project currently basically has the playrho and playrho::d2 namespaces. Many declarations for implementations that users should never touch directly however exist right in those same namespaces. I'd prefer for implementations that should never be user accessible to be in deeper namespaces like playrho::d2::implementation. Sometimes a nested namespace name of detail gets used for reasons like this and it is in PlayRho already, but I've saved it for stuff that would still be accessible in user code.

I'd like to hear what suggestions others might have for this and I'd like to address this before going to beta since this will of course require user code to change to adapt to this.

Actual Behavior:

The organization of files in the file-system seems more oriented towards concepts like Common, Dynamics, and Collision and less oriented to user access and namespaces.

Steps to Reproduce the Actual Behavior:

Take a look at the files and directories under PlayRho.

[louis-langholtz]

Here's a working example of the namespace organization planned:

namespace playrho {

namespace detail {
template <std::size_t N> struct AABB; // Current
template <typename T, typename Tag> class IndexingNamedType; // Moved from playrho::strongtype
} // namespace detail

using BodyID = detail::IndexingNamedType<BodyCounter, struct BodyIdentifier>; // Current

namespace d2 {
using AABB = detail::AABB<2>; // Current
class World; // Current
} // namespace d2

namespace d3 { // Planned
using AABB = detail::AABB<3>; // Planned
class World; // Planned
} // namespace d3

} // namespace playrho