Do not return extra result from tuple:__index method.

Marshall replication using the primary port.

Split iproto requests into two categories: DML and admin.  Change
PING request code to 64, to lay within admin request range.
Perform administrative requests synchronously, without pushing
them into an event queue.
Add a new administrative request, IPROTO_SUBSCRIBE.

Use dynamic memory for struct iproto_request. Introduce memory
management.

Remove replication_port from the configuration file and
update tests.

Fix the test runner so that it correctly generates
replication_source to point to the primary port.
Add variable arguments to IllegalParams.
Move replia-related recovery methods to a new header, replica.h.

Remove a debug printout from box.net.lua

Update tests.

 + memory leak in box.net.box (timeouted responses)
 + remote:ping() never throw exception

Closes #161

Fix styler
Clarify tricky pieces of the code (at least make them clearer to yours
truly).
Fix a bug with incorrect return value from fwrite() & O_DIRECT.

This fix adds virtual method raise() to Exception classes to throw
derived type instead of base.

This patch explicitly saves Exception to a thread-local variable inside
struct cord on tnt_raise(). This variable can be used to safetly
re-throw last exception from any place (not only from catch() block).
This technique requires exception to be thrown and catched by pointers.
tnt_raise macros was rewritten and all 'catch (Exception &)' blocks were
substituted with 'catch (Exception *e)'.

This patch also adds a new feature to box.raise() function.
When called without arguments box.raise() re-throws last exception (if
any).

These changes needed to implement proper handlings of exception for FFI
calls.

Implement cord names.
Log cord names in the server log.
Try to make find_path() valgrind-clean (the bug, however,
is in glibc).

move module related tests from test/box/ to test/module/.

shortcut :count method

remote:call always returns lua-table.

Remove an extra block offset.

Check that tuple is an msgpack array.

Summary:
* PLUGIN_DIR -> MODULE_DIR
* MODULE_DIR prefix is /usr/lib/tarantool/VERSION
* MODULE_DIR automatically appends to both lua c/path
* removed plugin autoload facility in src/lua/init.cc
* removed admin console plugin dependencies
* moved src/box/lua/sql.lua to separate module = require('box.net.sql')
* moved src/plugin/pg = require('box.net.pg')
* moved src/plugin/mysql = require('box.net.mysql')
* default .so and .lua install is lib/tarantool/modules/{box/net/}
* debian spec and tests are updated