Implements:
* image_ops_create
* image_ops_update
* image_ops_delete
* font_ops_create (Using cairo w/ freetype2)
* script_ops_draw_line
* script_ops_draw_triangle
* script_ops_draw_quad
* script_ops_draw_rect
* script_ops_draw_rrect
* script_ops_draw_arc
* script_ops_draw_sector
* script_ops_draw_circle
* script_ops_draw_text
* script_ops_begin_path
* script_ops_close_path
* script_ops_fill_path
* script_ops_stroke_path
* script_ops_move_to
* script_ops_line_to
* script_ops_bezier_to
* script_ops_push_state
* script_ops_pop_state
* script_ops_transform
* script_ops_scale
* script_ops_rotate
* script_ops_translate
* script_ops_fill_color
* script_ops_fill_linear
* script_ops_fill_radial
* script_ops_fill_image
* script_ops_stroke_width
* script_ops_stroke_color
* script_ops_line_cap
* script_ops_line_join
* script_ops_miter_limit
* script_ops_font
* script_ops_font_size
* script_ops_text_align
* script_ops_text_base

Signed-off-by: Jon Ringle <[email protected]>

This matches what is done similarly in glnvg__allocTexture() in the nvg
code to generate ids to use for looking up image data. This change will
remove the 32-bit constraint that was previously done with cairo images
and allow cairo to build on 64-bit architecture.

This is useful to either run scenic_driver_local with:
 * gdbserver
 * valgrind

For example, you could now have in your config:
`debugger: "gdbserver :5555"`

which will wait for you to attach gdb with a remote target on port 5555 and
set breakpoints and step through code

valgrind is useful for debugging memory issues such as malloc/free, memory
overruns and memory leaks.