Revert "Create metapod_core for the operators implementation and void the double ref pb."

This reverts commit aa51c1b83ad074e6e19aca2397ccc1792533fc0d.
Revert "Add operators implementations for cm-anyaxis in source file."

This reverts commit 609794457771f22cc89da6bebf929cbf5fbd03cf.
Revert "Add operators implementation for cm-freeflyer in source file."

This reverts commit 07a625a48f91ffc7b5dea518893971e964d02a13.
Revert "Add operators implementations for cm-oneaxis in source file."

This reverts commit 789d4ada4853f32fb32f9fe61cd89024db53d551.
Revert "Add operations implementation for transform in source file."

This reverts commit 5a67bdeee983db1430dca933da0c9900a2d59e53.
Revert "Remove operators implementation from transform."

This reverts commit 282237ff4af5a7b7f10dbed8e50a5d3aca3a51f4.
Revert "Remove operators implementations for inertia."

This reverts commit 8b551d4f3c8a18351c24aff02d51771f0d8dbf3d.
Revert "Put operators implementation in source file."

This reverts commit b29d60cc080bddf4e17c18becd2451e7d8a27e21.
Revert "Operators not templated must be in source file not in headers."

This reverts commit d9f1c51a9c8b773a3d694dd9714cbce4e28a326c.
Revert "Operators implementation must be in a source file not a header."

This reverts commit 1de0c0980801df839603e6e7eb9399c0b72dc399.
Make all the methods on line and remove constantness for S on oneaxis.

This seems not to impact the benchmarks.