[web2py] new features in trunk: detect_record_change

[Massimo Di Pierro]

Two changes in trunk:

1)

    form.accepts(request)

is now the same as 

    form.accepts(request.post_vars)

2) before you had three options:

form=SQLFORM(table,record)
if form.accepts(request):
     response.flash="record updated"
elif form.errors:
     response.flash="errors in form"
else:
     response.flash="form not submitted"

Now you have four options:

form=SQLFORM(table,record,detect_record_change=True)
if form.accepts(request):
     response.flash="record updated"
elif form.errors:
     response.flash="errors in form"
elif form.record_changed:
     response.flash="other user has changed record before you did"
else:
     response.flash="form not submitted"