Revert "Fixed compilation with GCC 4.9."

The final release doesn't have the issue with non-explicit
default std::vector constructor. Most of the conflicts resulted from
Mesh::Primitve -> MeshPrimitive refactoring.

This reverts commit c2ad09706e2bae00581b9942041e0e8c91c4bb03.

Conflicts:
	src/Magnum/Primitives/Capsule.cpp
	src/Magnum/Primitives/Circle.cpp
	src/Magnum/Primitives/Crosshair.cpp
	src/Magnum/Primitives/Cylinder.cpp
	src/Magnum/Primitives/Icosphere.cpp
	src/Magnum/Primitives/Implementation/WireframeSpheroid.cpp
	src/Magnum/Primitives/Line.cpp
	src/Magnum/Primitives/Plane.cpp
	src/Magnum/Primitives/Square.cpp
	src/Magnum/Primitives/UVSphere.cpp
	src/Magnum/SceneGraph/Object.hpp
	src/Magnum/Text/GlyphCache.cpp
	src/Magnum/TextureTools/Atlas.cpp
	src/Magnum/TextureTools/Test/AtlasTest.cpp