Update eosio-s2wasm to generate new style call_indirect

integrate slim net plugin

Remove nonce from system contracts; use nonce on nobody

This move of the submodule gives us an eosio-s2wasm that generates "new" call_indirect syntax. While cleos will accept either old or new call_indirect syntax, it's easier to interoperate with external tools by using the new syntax.

build net_api_plugin, link in net, net_api and txn_test_gen plugins, create something that calls the accepted_transaction signal

fix most of the unitests in delay_tests.cpp

Gh#2738 buyram newaccount

non producing node support

Contract destructor call

get_account API call should return info from totalband and voters tables in system contract, draft of pretty printing cleos get account #2661