--force-drop-function command line parameter added.

[vchimishuk]

Hi. I had some problems with updating functions with your diff utility. When function's signature were changed CREATE OR REPLACE statement fails, so I have added new --force-drop-function command line key to insert DROP FUNCTION statement before any CREATE OR REPLACE statement for existing functions. This is a little redundant, but it works. It is hard to me to differ function signature change situations and insert DROP FUNCTION only in that case. So, in some case this pull request can be interpreted as bug report, it is better to replace my patch with handling signature change situations and generates DROP FUNCTION only for such situations. Best regards, Viacheslav.

[fordfrog]

hi, could you please provide some test cases where apgdiff fails without your patch? i just reviewed apgdiff code and it should parse function signatures and behave accordingly. but sure there might be a bug which causes it fails in some cases.

[chadfurman]

This PR is over 4 years old with no follow-up. I'm closing it if I don't hear from @vchimishuk soon.