Fixes #147.
Add cache for server discovery
Ensure we have a recent enough version of xmpp-ftw-buddycloud
Remove segfault-handler it doesn't appear to install any more
Reinstate segfault-handler
Merge pull request #192 from buddycloud/cache

Add cache for server discovery
using proper namespaces for affiliations retrieval
Fixing affiliations tests
Merge pull request #193 from buddycloud/develop

Merging with develop