Make request->tuple to be iovec
Add alloc_factor argument to obuf_create()
Add obuf_ensure() and obuf_advance() API
Merge with master
Replace tbuf with obuf
Introduce BOX key type for R-Tree
Add unit tests for R-Tree
Add unit tests for R-Tree
Remove an incorrect and useless assert (fixes gh-535).
Merge remote-tracking branch 'origin/master' into gh-291-call-result

Conflicts:
	src/box/tuple.cc
	src/box/tuple.h
Fix a crashing slab_cache.test (not patched after introduction of quotas).
converted rtree to plain c, moved it to salad
gh-291: tbuf erasure review fixes. Erase a bit more.

Fix a bug in iovec_join which would overwrite data of
the first iovec with subsequent iovecs.
Double the default buffer size.
Merge branch 'master' of github.com:tarantool/tarantool
Merge remote-tracking branch 'origin/master' into rtree-v4
brought back area_t definition, added sq_coord_t type, avoided DBL_MAX dependance
added several comments to rtree.h
Merge branch 'rtree-v4' of github.com:tarantool/tarantool into rtree-v4
Review fixes (rtree-v4).
rtree-v4, review fixes

Weed out 'box' data type for now. A special name can backfire
in the future, when we exteend HASH/TREE/other types.

Add checks for uniqueness.

Disable check of key parts, it was not used any way,
since an explicit check is made in initIterator() and findByKey().

Mark sophia engine as  not supporting RTREE.