Removing pgr_ prefix & some formatting & cleanup

[cvvergara]

Changes proposed in this pull request:

• PickDeliveryOrders_t -> Orders_t
• pgr_global_report -> 'vrp_global_report`
  • & free the memory of the messages
• alloc.*
  • adding: namespace vrprouting
  • pgr_fn -> fn
• postgres_connection.*
  • pgr_SPI_fn -> vrp_SPI_fn
  • prepares the file to be included in C++
  • remove unused code
• class Pgr_message -> class Message
• (vroom.hpp) preparing separate on another PR the implementation from the header
  • reformatting to 4 spaces
• f.c & f_driver.*
  • reformatting to 4 spaces
  • all drivers
  • only static process
  • removing doxy dic of static process
  • *.c removing useless comments (like the sql comment that is never mantained)
  • removing directive about PGSQL_VERSION > 95
• sql/vroom
  • remove vrp_ from filenames

@pgRouting/admins

[cvvergara]

Note that doxygen documentation is failing (because the update now catches things)
That I dont care much at this moment as there are more PR pending because of the code change to read the queries in C++.
Many fails are happening in code will be changed.

[sanak]

Looks good to me !
(I will try macOS local build/test from around next PR. 😊)