Don't check for gstate->target == NULL anymore as the API now guarantees it never occurs.
Check that path->status is a valid status value and cause an INVALID_STATUS error otherwise.
Test the new CAIRO_STATUS_INVALID_STATUS error case in cairo_append_path.
Port to use new cairo_create interface.
Rewrite all tests that were using cairo_set_target_surface to instead create a temporary cairo_t, (eventually to be replaced with cairo_begin_group).
Add new cairo_path_t, containing a cairo_path_data_t array and an explicit length. Remove CAIRO_PATH_END_PATH terminator from cairo_path_data_t.
Rename the internal path object from cairo_path_t to cairo_path_real_t.
New functions: cairo_copy_path_data, cairo_copy_path_data_flat, and cairo_append_path_data.
Add new implementation for cairo_copy_path_data and cairo_append_path_data.
New test for new path_data functions.
