cfbimgblt.c

Hi, 

I want to address some of the limitations of cfbimgblt.c, but
unfortunately I ended up practically rewriting the whole code.  In
theory, the code (slow_imageblit): 

a. supports all possible bit depths 
b. should be able to handle destination writes that are not aligned by
an unsigned long 
c.  should be able to handle fix->line_length not a multiple of an
unsigned long 
d. framebuffer access is always the size of an unsigned long and aligned
e. preliminary code for drawing the logo. 
f. added Paul Mackerra's endianness patch (plus some of my own), but I
have no big-endian machine, so it's untested, and perhaps incorrect. 

The only tests I've done for slow_imageblit is at 8, 16, 24, and 32 bpp,
and forcibly misaligning image->dx by 1 pixel. The code is slow, so I
included fast_imageblit for 8, 16 and 32 bpp which is an implementation
of fbcon-cfb8/16/32.c. 

Tony