Some resource URLs generated with '//' in path

Some resource URLs are generated with a '//' (instead of a single '/') in the path, which leads to display errors in certain cases.
This is due to an inconsistent use of the $config->resourceBase variable, as some files and templates in CiviCRM add a '/' after it when they should not as it already ends with a trailing '/' in all cases. This leads to the display of a broken image in certain hosting configurations.

Correction:

• replace the 2 instances of ''/i/' with 'i/' (no leading /) in file CRM/Campaign/Page/DashBoard.php
• replace the 27 instances of 'resourceBase}/' with 'resourceBase}' (no trailing /) in various template files located in the templates directory