Added support for multiple URIs for LDAP server/hostname to LDAP authentication module. Resolves issue #2004. The code reuses the existing setting, but treats it as space-separate list of URIs. Modifed the TBGContext error-handling function to ignore errors caused by function calls that were called with error control operator ('@').
Make sure that the Sortable is re-created when new items get added to a list. Fixes issue #2016.
Added function that retrieves the next ordinal number for an item in an issue field, used for sorting purposes. Updated the TBGDatatypeBase class to have a _preSave method which will set the order for an item to this number if the order is null. Resolves issue #2017.
Merge pull request #178 from azaghal/branch-32

Support for multiple LDAP URIs for LDAP Authentication