LCD core move buf ptr and address look up function viewport struct

I'm currently running up against the limitations of the lcd_draw functions
I want these functions to be able to be used on any size buffer not
just buffers with a stride matching the underlying device

[DONE] allow the framebuffer to be decoupled from the device framebuffer
[DONE need examples] allow for some simple blit like transformations
[DONE] remove the device framebuffer from the plugin api
[DONE}ditto remote framebuffer
[DONE] remove _viewport_get_framebuffer you can call struct *vp = lcd_set_viewport(NULL) and vp->buffer->fb_ptr

while remote lcds may compile (and work in the sim) its not been tested on targets

[FIXED] backdrops need work to be screen agnostic

[FIXED] screen statusbar is not being combined into the main viewport correctly yet

[FIXED] screen elements are displayed incorrectly  after switch to void*

[FIXED] core didn't restore proper viewport on splash etc.

[NEEDS TESTING] remote lcd garbled data

[FIXED] osd lib garbled screen on bmp_part

[FIXED] grey_set_vp needs to return old viewport like lcd_set_viewport

[FIXED] Viewport update now handles viewports with differing buffers/strides by copying to the main buffer

[FIXED] splash on top of WPS leaves old framebuffer data (doesn't redraw)
[UPDATE] refined this a bit more to have clear_viewport set the clean bit and have skin_render do its own screen clear
scrolling viewports no longer trigger wps refresh
also fixed a bug where guisyncyesno was displaying and then disappearing

[ADDED!] New LCD macros that allow you to create properly size frame buffers in you desired size without wasting bytes
(LCD_ and LCD_REMOTE_)
LCD_STRIDE(w, h) same as STRIDE_MAIN
LCD_FBSTRIDE(w, h) returns target specific stride for a buffer W x H
LCD_NBELEMS(w, h) returns the number of fb_data sized elemenst needed for a buffer W x H
LCD_NATIVE_STRIDE(s) conversion between rockbox native vertical and lcd native stride (2bitH)
test_viewports.c has an example of usage

[FIXED!!] 2bit targets don't respect non-native strides
[FIXED] Few define snags

Change-Id: I0d04c3834e464eca84a5a715743a297a0cefd0af

apps/plugins/lib/xlcd_draw.c

@@ -349,6 +349,9 @@ static const fb_data graylut[256] = {
 void xlcd_gray_bitmap_part(const unsigned char *src, int src_x, int src_y,
                            int stride, int x, int y, int width, int height)
 {
+    size_t dst_stride;
+    fb_data *lcd_fb = get_framebuffer(NULL, &dst_stride);
+
     const unsigned char *src_end;
     fb_data *dst;
 
@@ -377,7 +380,7 @@ void xlcd_gray_bitmap_part(const unsigned char *src, int src_x, int src_y,
 
     src    += stride * src_y + src_x; /* move starting point */
     src_end = src + stride * height;
-    dst     = *rb->lcd_framebuffer + LCD_WIDTH * y + x;
+    dst     = lcd_fb + dst_stride * y + x;
 
     do
     {
@@ -398,7 +401,7 @@ void xlcd_gray_bitmap_part(const unsigned char *src, int src_x, int src_y,
 #endif
 
         src +=  stride;
-        dst += LCD_WIDTH;
+        dst += dst_stride;
     }
     while (src < src_end);
 }
@@ -416,6 +419,9 @@ void xlcd_gray_bitmap(const unsigned char *src, int x, int y, int width,
 void xlcd_color_bitmap_part(const unsigned char *src, int src_x, int src_y,
                             int stride, int x, int y, int width, int height)
 {
+    size_t dst_stride;
+    fb_data *lcd_fb = get_framebuffer(NULL, &dst_stride);
+
     const unsigned char *src_end;
     fb_data *dst;
 
@@ -444,7 +450,7 @@ void xlcd_color_bitmap_part(const unsigned char *src, int src_x, int src_y,
 
     src    += 3 * (stride * src_y + src_x); /* move starting point */
     src_end = src + 3 * stride * height;
-    dst     = *rb->lcd_framebuffer + LCD_WIDTH * y + x;
+    dst     = lcd_fb + dst_stride * y + x;
 
     do
     {
@@ -471,7 +477,7 @@ void xlcd_color_bitmap_part(const unsigned char *src, int src_x, int src_y,
         while (src_row < row_end);
 
         src +=  3 * stride;
-        dst += LCD_WIDTH;
+        dst += dst_stride;
     }
     while (src < src_end);
 }