SUMMARY:
The decompression code is now built into ov511.o by default. This makes the
code simpler and should make the user experience better. You can still disable
the OV511 and/or OV518 decompressors in the Makefile if you need to.

PER-FILE CHANGES:
Makefile:
- Make decomp modules "built-in" to ov511.o

README:
- Update info on compression support

ov511.c:
- Remove decompression module interface, replace it with a much simpler linkage
- Add a "can_decompress" flag to /proc info file; tells whether appropriate
  decompression code was compiled in.

ov511.h:
- Remove dead parts of decompression module interface, add
  OV51[18]_SET_DECOMP_OPS() macros

ov511.txt:
- Fix up the install instructions a bit

ov511_decomp.c:
ov518_decomp.c:
- Remove decompression module interface
- Make the license info a bit less verbose