To do:
======
- implement coarse calibration to determine settings for analog-front-end
  All CCDs encountered so far seem to need about the same settings however.

- Store analog calibration data somewhere.
  Use currently used values as default.

- Suggestions by Marcin Cieslak:
	- clean up structures
	- clean up namespace
	- clean up source formatting ('indent --gnu' ?)


- implement real calibration, using 12 bit data at 600 dpi
  instead of 8 bit data.at 150 dpi.
  -> is now at 600 dpi, not yet at 12 bit

- design a mechanism to set the scan and calibration areas
  a) part of HWProps structure, or
  b) set by user at first scan

- further investigate scanner registers
  a) study backtracking register more
  b) identify bits in bit-oriented registers.

- add more error checking ('sanity checking') on parameters

- figure out what the USB interrupts mean that sometimes occur.



Done
====

- Get rid of mytypes.h / fix types
  Now an int is implicitly assumed to be 32 bit.

- make backend comply with tstbackend
-> all externs and publics removed when compiling towards sane

- implement sane_cancel properly
-> done by ullsig

- implement timing mechanism for scanner lamp
  so scanning can only start if the lamp was already on for 30 seconds
Possible implementation:
On startup: if lamp is off, turn it on and start timer
On scan: if lamp is off, turn it on and start timer. Wait for timer expiry.
On exit: if scanner chip is niash00012 then turn off lamp,
  otherwise let the scanner turn it off automatically
-> Implemented by Ullrich Sigwanz

- try out parallel port scanning on HP3400/4300
-> parallel port support will be dropped, no people to test/develop it

- investigate vertical resolution setting of hp3400/4300.
-> experiment with the motor table, formula is already known to generate it
-> 600 dpi is possible by doubling most values in the table
-> 150 dpi can be done by using register 0x06 to skip every other line

- Add separate gamma tables for R, G, B. This should be easy (look at how
  other backends do it) but is not really required yet.
-> not required