fixed many memory leaks

added working shadows, using basic shadow mapping

btgui/OpenGLTrueTypeFont/fontstash.cpp

@@ -789,6 +789,8 @@ void sth_delete(struct sth_stash* stash)
 	tex = stash->textures;
 	while(tex != NULL) {
 		curtex = tex;
+		delete tex->m_texels;
+		tex->m_texels=0;
 		tex = tex->next;
 		stash->m_renderCallbacks->updateTexture(curtex,0,0,0);
 		free(curtex);

btgui/OpenGLTrueTypeFont/opengl_fontstashcallbacks.cpp

@@ -180,6 +180,7 @@ void InternalOpenGL2RenderCallbacks::updateTexture(sth_texture* texture, sth_gly
 
 				glDeleteTextures(1, id);
 				//delete id;
+				delete texture->m_userData;
 				texture->m_userData = 0;
 			}
 

btgui/OpenGLTrueTypeFont/opengl_fontstashcallbacks.h

@@ -7,6 +7,7 @@ class GLPrimitiveRenderer;
 
 struct	InternalOpenGL2RenderCallbacks : public RenderCallbacks
 {
+
 	virtual PrimInternalData* getData()=0;
 
 	virtual ~InternalOpenGL2RenderCallbacks();