Use "plain" instead of "raw" as suffix in function name to denote plain integers. #8

In the pick Deliver functions, we have both the signatures - to take timestamps as input, and to take plain integers as input.

The function for the plain integers is suffixed with "raw". Changing it to "plain" would be more relevant.

Sample Links:
https://github.com/pgRouting/vrprouting/blob/develop/src/pickDeliver/pickDeliver.c#L64
https://github.com/pgRouting/vrprouting/blob/develop/src/pickDeliver/pickDeliver.c#L97
https://github.com/pgRouting/vrprouting/blob/develop/src/pickDeliver/pickDeliver.c#L246
https://github.com/pgRouting/vrprouting/blob/develop/src/pickDeliver/pickDeliver.c#L352