Reported by Tony Cooper, Mar 5, 2011

Allow a user to do partial file commits. That is, if the partial 
commits option is specified in the ci command, present the user with 
the differences encountered in each file, one file at a time, and 
for each distinct difference allow the user to answer `yes, no, 
accept all for this file, accept none for this file, next file'.

Cheers,

Tony.