Using key field instead of value in multiselect fields

Issue Summary

Hello.

This was my solution to export multiselect fields from the webform into sugarcrm, here is some description about the problem:

- Webform contains multiple checkboxes, which should be populated on a listbox into sugarcrm depending on being checked or not.
- webform2sugar module exports the selected checkboxes, sending their value instead of their key on form submission, i.e.

- A list box field is created in sugarcrm with the pairs: "somekey=>somevalue" and "somekey2 => somevalue2" ;
- The checkboxes in the webform have the corresponding options: "somekey|somevalue" and "somekey2|somevalue2" ;
- a checkbox with the pair "somekey|somevalue", when checked sends "somevalue" to the listbox, which is not recognized, simply because it was expecting "somekey" ;
- Result: A list box is populated in sugarcrm with and empty value (The list bullet appears, but the text is empty).

Solution:

- My solution is pretty straightforward but perhaps some feedback will make it more simple;
- I made a version of the function "webform2sugar_check_safe_key" which returns the $key instead of the value
- Replaced the "webform2sugar_return_safe_key" call with the new function call on the multiselect foreach cycle;

I'm sorry for not using git and applying a diff file, but with some help and feedback I would happily do it.