Extend base Connection class to support a list of nodes and an
optional Strategy parameter to choose next item from this list.

Add built-in reconnect strategy class based on Round-Robin alg.
@params:
- addrs, list of maps {'host':(HOSTNAME|IP_ADDR), 'port':PORT}.

Return next connection or an error if all URIs are unavailable.

Closes #106

Add missing inconnect = false.
This bug leads to only one disconnection allow.

Needed for #106

closes gh-43

closes gh-90

closes gh-82

closes gh-89

closes gh-88

closes gh-46

* Reloading of schema on Tarantool schema error (closes gh-63)
* Rewrite request using collections.Sequence
* Delete RETRIES on completion status == 1 (no this completion status,
  anymore, also closes gh-45)
* flush schema now, also, loads schema from server.
* Modify/Simplify schema internals
* Added absent constants
* Updated errorcodes (closes gh-69)
* Schema is now flushed, upon successfull authentication (closes gh-68)

Proofed to work on py27, py35 and pypy

If iterator type isn't given and key is empty, then select everything from space
(even on HASH index)
closes gh-76

+ fix for TypeError: cannot concatenate 'str' and 'Response' objects

fix work with socket on windows

Don't even send OK

>>> import tarantool
>>> tarantool.connect('48.12.22.123',3311)
```
Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    tarantool.connect('48.12.22.123',3311)
  File "C:\Python27\lib\site-packages\tarantool\__init__.py", line 47, in connect
    encoding=encoding)
  File "C:\Python27\lib\site-packages\tarantool\connection.py", line 93, in __init__
    recv = self._sys_recv = libc.recv
  File "C:\Python27\lib\ctypes\__init__.py", line 378, in __getattr__
    func = self.__getitem__(name)
  File "C:\Python27\lib\ctypes\__init__.py", line 383, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: function 'recv' not found
```

Fix 1.7 JOIN implementation: don't send OK if the server replied with an
error.

Modify docstrings for tarantool.Connection methods
Modify docstrings for tarantool.Space methods
Add basic tests for upsert/eval.
Modify tarantool.Space for simplicity of code/understanding
Add tests for space, fix couple of errors in code