Also the initial public key of the 'eosio' account can now be specified
in CMake rather than specifying the chain ID.

Also fixed special accounts initialization and special_accounts_tests.

Moved special_accounts_tests and wallet_tests into unittests.

Don't set the cmake variable OPENSSL_LIBRARIES. It's very clear from the documentation that that's an output variable. Not an input variable.

This resolves a benign but worrisome warning from cmake on chainbase_test.

cmake requires that cmake_minimum_required() occurs first thing in the cmake file. Yes, even before project()! Not doing this leads to some spooky things, one of which was the need for us to manually stuff -std=c++14 in to the build flags for macOS. Fix that issue; bump cmake requirement to 3.5 since it is the minimum we've tested with; and make it clear all platforms will use gnu++14 for now.

use gnu++14, part of our use of BOOST required extended numeric literals.  The resolution was "-std=gnu++11 or -fext-numeric-literals"