Bug 17016: Button to clear all fields in budget planning

Bug 17016: Button to clear all fields in budget planning

Currently there is no way to undo the 'auto-fill'. This
patch adds a 'clear' option that resets the row.

To test:
1) Go to Admin --> Budgets
2) Click a budget
3) Click Planning -> any option
4) Test the Auto-fill button to see what it does
5) Apply patch and refresh page
6) Should now be a Clear button
7) Auto-fill the row then click Clear button. Confirm it clears all
fields and sets the fund remaining back to the original amount and
styles.
8) Add another fund and confirm that this still works with multiple
funds.

Sponsored-by: Catalyst IT
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Bouzid Fergani <bouzid.fergani@inlibro.com>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>