Fixes #16850: Add config folder for customization files
Support including config file multiple times for custom_strings_inc.php
Update config_inc.php location in TestConfig
Update Travis to make config folder writable.
Changed chmod to be recursive for Travis.
Moved chmod to apply for all php versions not just 5.3.
Merged latest from master
Merged latest form master 2.
Rename all webservice configs options to webservice_* instead mc_*
Add support for MANTIS_CONFIG_FOLDER instead of MANTIS_CONFIG
Fixes with handling of global variables.
Fix include errors.
Relationship include fix.
Use config_get_global() for getting config_path in relationship_api.
Remove hard coded instances of config folder references
Fixed error where absolute_path was not defined.
Remove custom_strings_file config.
Updated checks page with config folder related updates.
Install page detects and complains about configs in old location.
Fixes #17184: Anonymous authentication to soap api.

Anonymous authentication now works by passing in an empty user name
or the anonymous user name.  In both cases, the password field should
be left blank.  The authentication logic has been pushed into the
script login validation core API.