Reorganizing the techniques

Hi,

Currently, the AUWG techniques are organized into 4 files, one for each 
of the old guidelines.

Unless there are objections, I would like to merge these so that we will 
have just two files, one for Part A (accessible ui) techniques and one 
for Part B (accessible content) techniques.

If you have a problem let me know ASAP.

Cheers,
Jan