aareadme in ~/genv10Updates/chgen/src - RJL 98/9/12

I updated gen_defines (not cvs ci yet) and gen_pr_delete (checked in).

Surprise: I did cvs co  on gen/ver_10log and the doc/*.tex UG says 
gen_pr_log will generate pr_log.c, but it is not present 
in gen/test/housedb when I run 'sh build' there.?
(I added calls to pr_start_log and pr_stop_log in main of house.c,
but it won't compile with these calls not linked to pr_log.c