ENUM0 macro.

Blueprint https://blueprints.launchpad.net/tarantool/+spec/error-injection

client/tarantool: proper error display

test/connector_c: sql select limit test
client/tarantool: error processing fix

Continue improving valgrind run: add recommended luajit suppressions.

Workaround a valgrind warning in strtod on 64 bit systems.

On 64-bit systems, strtod uses an optimized version of
strcasecmp to find out whether or not a string represents
a number.

This version uses int (8 byte) comparison. If the string
in turn is less than 8 bytes, or is not aligned around 8 byte
boundary, uninitialized memory can be accessed.

Work this around with a simple test (this is lame and
incomplete, but covers our cases. In future either
this in valgrind will be gone, or our code will change,
or we add a suppression).

Fix a valgrind warning in sptree.h discovered by new tests.

test/connector_c: tnt_reply test added

Rewrite addr2symbol binary search: make it simpler,
fix bugs with access to symbols[-1], make sure it works
correctly on 64 bit systems (s/int/ssize_t).

Add a way to do nested iteration in Lua stored procedures.
Implement destruction for tree indexes and iterators.
This clears a few valgrind warnings.

Fix connector_c test.

Finish porting index API to objective C.
Change all methods to become objective C methods.
Implement a family of virtual constructors and destructors.
Change iterator allocation scheme.