Code cleanup

Patch attached with the following changes:
- Replaced the uc_edi_get_delimiter() function with a string, no need for function call overhead.
- Replaced the uc_edi_default_order_import_rules() function with a string, no need for function call overhead.
- Changed the $order parameter of the uc_edi_generate_order_export() and uc_edi_generate_order_product_export() functions from an order object to an order object reference for efficiency.
- Replaced the uc_edi_default_order_export_pattern() function with a string, no need for function call overhead.
- Replaced the uc_edi_default_order_product_export_pattern() function with a string, no need for function call overhead.
- Replaced 'uc_edi_order_export_product_line_number' Drupal variable with php variable.
- Replaced the uc_edi_admin_help() function with hook_help().
- Consolidated the uc_edi_order_admin and uc_edi_order_admin_form functions.
- Fixed variable names in the .module file to match that in the .install file.
- General code and comment cleanup.

Cheers,

Antoine

Updated the changes against head and committed the attached patch.

Cheers,

Antoine