Add many missing VDP commands.

[robogeek42]

Add commands for many missing VDP commands including those for buffered commands.

[robogeek42]

These are the additional commands:

vdp_write_at_text_cursor( void )
vdp_write_at_graphics_cursor( void )
vdp_enable_screen( void )
vdp_page_mode_on( void )
vdp_page_mode_off( void )                                                                                                                                                           vdp_reset_graphics( void )
vdp_disable_screen( void )                                                                                                                                                          vdp_set_graphics_colour( int mode, int colour )
#define vdp_gcol( M, C ) vdp_set_graphics_colour( M, C )
vdp_define_colour (int logical, int red, int green, int blue )
vdp_swap( void )
vdp_redefine_character( int chnum, uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5, uint8_t b6, uint8_t b7 )
vdp_scroll_screen_extent( int extent, int direction, int speed )
vdp_scroll_screen(int direction, int speed)
vdp_reset_viewports( void )                                                                                                                                                         vdp_set_graphics_viewport( int left, int bottom, int right, int top )
vdp_set_text_viewport( int left, int bottom, int right, int top )
vdp_filled_rect( int x, int y )                                                                                                                                                     vdp_solid_bitmap( int width, int height, int r, int g, int b, int a )
vdp_clear_sprite( void )                                                                                                                                                            vdp_add_sprite_bitmap( int n )
vdp_adv_write_block(int bufferID, int length)
vdp_adv_clear_buffer(int bufferID)                                                                                                                                                  vdp_adv_create(int bufferID, int length)
vdp_adv_stream(int bufferID)
vdp_adv_adjust(int bufferID, int operation, int offset)
vdp_adv_consolidate(int bufferID)                                                                                                                                                   vdp_adv_select_bitmap(int bufferId)
vdp_adv_bitmap_from_buffer(int width, int height, int format)     

Includes a convenience #define for vdp_gcol as it strays from the usual naming style, but it is easier to type!

Note, there is also a critical style/usage fix for vdp_cursor_tab()
Which was "row, col" - that is (Y,X)

This differs from how it is used in BASIC - you would expect to do PRINT TAN(X,Y)

cheers

[astralaster]

Looks good in general, but please check the call a buffer function.

[astralaster]

I think this is a mistake and should be included?

[robogeek42]

I did start to add it, but I had no way of testing it as I don't really get the "commands in a VDP buffer" thing.
So, I thought it best I leave it out.
Certainly, I could just add it verbatim from the docs and hope it is correct.

(Would have been better to remove the commented code entirely I guess)

[astralaster]

Yes, it looks correct. Please add it.

[robogeek42]

Updated the head of my main to remove the commented code.
I think probably I would need to create a new PR with all the related "command buffer" VDP commands (1, and 6 though 13) so that they can be used together properly.

That way, this request just adds the graphics advanced buffer commands.

[astralaster]

Same as the declaration.

[astralaster]

Thats also a solution. :)