DAWN 379 - Restore block_tests

DAWN-385 - Salvage usable test cases from native_contract_tests

Fix applesedemo to work with either openssl 1.0 or 1.1

Message buffer bug

Eosio build fedora with mongo support

Add Producer Scheduler Version to Block Header & Validate It #1671

Dawn 610 context free actions

Fix testing in Jenkins

fix bug in multi_index::modify and add related test case

Merging master to avoid conflicts before creating PR for eosio_build_fedora_mongo

The bug caused secondary keys to not be updated in the DB by modify()
when the associated secondary index table row iterator was not already
in the cache because db_idx_find_primary overwrote the to-be-updated
value with the old value from the DB.

Change push_nonce, now called push_dummy, test code to use a require auth action since nonce is context free.