* Rewrite box_net.{pg,mysql}.test.lua, so line wrappings won't matter.
* Testing System: 'RelWithDebugInfo' closer to Release, than to Debug
* Compiling on clang -> additional OP, cause of garbage after
  `iproto_request_type_strs` (Failed admin and other tests)

When panic() is called from a fiber != sched, we
call atexit handlers and free all memory, including
runtime memory, including the memory used for fiber
stack.

Thus essentially freeing memory the fiber's stack is
using.

The very next instruction using the stack gets
a SIGSEGV afterwards.

Perhaps don't be so strict about freeing resources at
shutdown and do not shoot yourself in the foot.

Conflicts:
	test/module/net_sql.common.lua
	test/module/net_sql.common.result
	test/module/net_sql.common.test
	test/module/net_sql.mysql.lua
	test/module/net_sql.mysql.result
	test/module/net_sql.mysql.skipcond
	test/module/net_sql.mysql.test
	test/module/net_sql.pg.lua
	test/module/net_sql.pg.result
	test/module/net_sql.pg.skipcond
	test/module/net_sql.pg.test
	test/test-run.py

purpose: OOS-build tests fail

Conflicts:
	.travis.yml
	client/tarantool/tc.c
	client/tarantool/tc_pager.c
	src/lua/yaml.cc

Needed for server/pg_type.h header

CMake is shipped with broken PosgreSQL script in most distros.
I had to copy this script and patch it to properly support
new versions of PostgreSQL.

purpose: OOS-build tests fail

deprecated connector_c tests

Add new system spaces _user and _priv to store users,
their passwords and their privileges.
Implement an authentication request in iproto protocol

Add a system space _func to store presistent information
about Lua functions. A function is now a subject
to ownership and privilege control.

Use MySQL-style sha1-double-hashing authentication by default.

Implement new Lua functions:

box.session.su()
box.session.uid()
box.schema.user.create()
box.schema.user.drop()
box.schema.user.grant()
box.schema.user.revoke()
box.schema.func.create()
box.schema.func.drop()

Store space creator in space definition.

What this patch doesn't implement:

- privilege checks in replication
- authentication of replication slaves
- exhaustive test coverage

Conflicts:
	src/box/tuple.cc
	src/box/tuple.h
	test/box/lua.result
	test/box/lua.test

This patch converts space:iterator() to be compatible with Lua
for-in loop conventions. The most important change is that
generating function now returns *state* as its first result:

    for _state, val in space.index[0]:pairs() do work(val) end

New syntax follows the best practices of Lua community and makes
index API to be more consistent with pairs() and tuple iterators.

This change partially restores pairs() logic as it was implemented
before 49875615.