Conflicts:
	connector/c/include/tp.h

Conflicts:
	src/box/box_lua.m

slab_class was an ambiguous name, get rid of it.
Minor cleanups in salloc.m (prepare for refactoring).

Move third_party library compilation to the top level (less
directory traversal).
Provide an option for using system LibEIO/libobjc.

Enforce a naming convention for cmake/ scripts
(Find* and Build*).

Move ev and eio wrappers to third-party (todo: delete
them completely).

There is one (known) problem with this patch:
tarantool --version now prints incorrect compile flags.
To be fixed in a separate patch.