Tear out admin CLI.

Also removed the metadata_change_handler_t logic, which existed only to support the admin CLI.
Collect files related to server metadata into an administration/servers/ sub-directory.
Remove some dangling references to the linenoise library.
WIP on server naming
Artificial tables, but currently on the the bare minimum of features are supported.
Merge branch 'next' into tim_remove_cli

Conflicts:
	src/clustering/administration/metadata.cc
Merge branch 'reql_admin' into tim_server_naming

Conflicts:
	src/clustering/administration/main/serve.cc
Make the server-name logic compile. Add an integration test.
WIP on server naming
Merge branch 'next' into reql_admin

Conflicts:
	src/clustering/administration/cli/admin_cluster_link.cc
Merge branch 'reql_admin' into tim_server_naming

This merge is necessary to get f626380f21cc43418892c4b12dc3196c3dfaf76a into tim_server_naming.
interface.server_name now works. Also, removed some debugf() calls.
Remove issue for machine name conflicts

Now that we automatically rename machines in case of a conflict, we don't need this anymore.
Add a polyglot test for r.server_rename().
Fix various minor issues that Daniel Mewes pointed out.
Fix some style checker issues.
Merge branch 'next' into reql_admin

Conflicts:
	src/clustering/administration/http/server.cc
	src/clustering/administration/main/serve.cc
	src/clustering/administration/namespace_interface_repository.hpp
Merge branch 'reql_admin' into tim_artificial_table_2
Merge branch 'tim_server_naming' into reql_admin

Conflicts:
	src/clustering/administration/main/serve.cc
	src/clustering/administration/reql_cluster_interface.cc
	src/clustering/administration/reql_cluster_interface.hpp
	src/clustering/administration/suggester.cc
	src/rdb_protocol/context.hpp
	src/unittest/rdb_env.cc
	src/unittest/rdb_env.hpp
Merge branch 'reql_admin' into tim_artificial_table_2