Test revoke a privilege from a role using a different grant path.

Conflicts:
	test/box/bsdsocket.result
	test/box/bsdsocket.test

Conflicts:
	test/box/bsdsocket.result
	test/box/bsdsocket.test

Implement granted privilege cache in struct user.

Reload user privileges from system spaces and
rebuild the cache whenever a grant or revoke occurs..

Implement revoking privileges from a role.
Basic tests pass.

Do not rebuild the privilege cache of objects
for which it can't have changed with a grant
or revoke.

Optimize rebuild_effective_grants().

Make role.test idempotent.

Make grant and revoke robust to malformed arguments.
Fix bugs in schema.lua, related to incorrect arguments
for grant/revoke.

Added method remote:reload_schema()

Conflicts:
	doc/user/connectors.xml
	doc/user/stored-procedures.xml
	doc/user/tutorial.xml
	src/coio.cc
	src/evio.cc
	src/evio.h

Provide fine-grained keepalive options on Linux, which
supports per-socket defaults.

Fix a bug with trying to set keepalive options for UDP
sockets - don't try to do it.

Introduce 'public' role.
Auto-grant 'public' to every user.
Update the snapshot.

On ARM chars are unsigned

This code didn't worked on ARM, changing the table and parameters to int seems to work fine on any platform.