Added implicit constructors for Mesh and IndexedMesh.

src/IndexedMesh.h

@@ -29,6 +29,16 @@ namespace Magnum {
  */
 class IndexedMesh: public Mesh {
     public:
+        /**
+         * @brief Implicit constructor
+         *
+         * Allows creating the object without knowing anything about mesh data.
+         * Note that you have to call setPrimitive(), setVertexCount(),
+         * setIndexCount() and setIndexType() manually for mesh to draw
+         * properly.
+         */
+        inline IndexedMesh(): _indexBuffer(Buffer::ElementArrayBuffer), _indexCount(0), _indexType(GL_UNSIGNED_SHORT) {}
+
         /**
          * @brief Constructor
          * @param primitive     Primitive type

src/Mesh.h

@@ -81,6 +81,15 @@ class Mesh {
             TriangleFan = GL_TRIANGLE_FAN
         };
 
+        /**
+         * @brief Implicit constructor
+         *
+         * Allows creating the object without knowing anything about mesh data.
+         * Note that you have to call setPrimitive() and setVertexCount()
+         * manually for mesh to draw properly.
+         */
+        inline Mesh(): _primitive(Triangles), _vertexCount(0), finalized(false) {}
+
         /**
          * @brief Constructor
          * @param primitive     Primitive type