Adds functions to order_by.
Adds a GET_FIELD_SHORTCUT flag to func_t.
Adds evaluation for descending terms.
Adds evaluation of DESC to order_by.
Adds tests for functional order_by.
Adds functional eq_join.
Adds tests for functional `eq_join`.
Adds docs for functional order_by.
Adds docs for functional eq_join.
Fix types in docs.
Docs should have been for rb not js.
Remove unneeded macro.
Don't crash on unrecognized shortcut.
Adds rql order_by test with 2 functions.
Merge branch 'next' into merge_br

Conflicts:
	src/rdb_protocol/func.cc
	src/rdb_protocol/func.hpp
	src/rdb_protocol/val.cc
	src/rdb_protocol/val.hpp