This is done to avoid situation, when two or more
fibers yield inside their try/catch blocks and
throws an exceptions. Seems like exception unwinder
stores some global state while being inside
a catch block.

This could lead to incorrect exception processing
and server crash.

The patch should use struct session, which is non-existent
in 1.5, so at least make session_storage_destroy a bit faster.

This patch implements show index and shows memory waste of the
slab allocator.

Fixes gh-153.

This patch also reworks title() to show role@custom_proc_title for all roles
as defined in the documentation.

A dead fiber could get reused prematurely or garbage collected twice.

This was because __gc could get invoked way after the fiber has
finished and reused for a different coroutine.

The fix is to always access fibers in Lua by fiber id.

Fix a hang on box.fiber.resume() of an attached fiber which gets
cancelled.
When the child fiber got cancelled before detach, the parent
never was woken up, and would hang forever.
Wake up the parent, and, in the parent, do not try to access
a dead fiber.

This patch limits maximum recursion depth for luaL_packsize and luaL_packvalue
functions to 16 nested tables. This check is needed to prevent a crash
on recursive Lua tables.

This patch adds lua_checkfield function - a wrapper for lua_tofield that raises
an error if Lua type can not be converted to lua_field structure. The function
should be used instead of lua_tofield in all bindings where custom types are not
supported.

Also don't call sfree_delayed if snapshot process isn't started, closes #118

The final version of odnoklassniki patch did not include the
most important part - delayed free of salloc memory.

Make a quick & dirty fix to the point.

Set signal handler for all signals, not just SIGTERM.
Print signal name to the log on exit.

Add constants for signal count. Rename. Coding style.

Do not use atexit() handlers, except the global tarantool_free()
function, which does nothing in the snapshot process.