aio-grab: cosmetics: style police: elementary coding style.
cosmetics + little bug

Apparantly at some time popen() was used, the file
pointer was still called "pipe", that's okay but
- pipe is a system call (and as such already defined)
- at one point pclose was used instead of fclose.
aio-grab: add support for vuplus solo2.

This should fix the screen grab from the web interface.

Credits to Captain <captain.onboard@web.de> for
the low-level stuff.
aio-grab: restructure decoder memory grabbing routines

Over the years, as new chipsets have been added,
the code has grown into a bit of a mess, with lots
of code duplication, irrelevant differences between
chipsets, etc.
Clean up everything, use common routines for
most chipsets.
aio-grab: fix 7335 dma config register address

copy/paste error introduced by
6a5a07f2b7437bfe6c7962c411baa29a9efd9ffb
aio-grab: fix chroma buffer size calculation

Allocated buffer was too large, mmap size was too small.

Reduce memory consumption and avoid segfaults for
certain video sizes (i.e. which aren't a multiple
of the chroma stride)
aio-grab: use correct chroma buffer limit

We cannot assume that the number of chroma lines
equals half the number of luma lines.
There are guaranteed to be more luma lines than
the vertical resolution, and more chroma lines
than half the vertical resolution.
But that does not make their relation exactly 2:1.
Use the reported number of chroma lines instead.
aio-grab: add 7424/7425 support
Merge remote-tracking branch 'pli/master': will need checking it still works for all box types, and update as needed.