Bitcoin Unlimited - Bitcoin Cash release 1.5.0.2

This is a minor bugs fix only release version based of Bitcoin Unlimited compatible
with the Bitcoin Cash specifications you could find here:

• https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/uahf-technical-spec.md (Aug 1st '17 Protocol Upgrade, bucash 1.1.0.0)
• https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/nov-13-hardfork-spec.md (Nov 13th '17 Protocol Upgrade, bucash 1.1.2.0)
• https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/may-2018-hardfork.md (May 15th '18 Protocol Upgrade, bucash 1.3.0.0, 1.3.0.1, 1.4.0.0)
• https://github.com/bitcoincashorg/bitcoincash.org/blob/master/spec/2018-nov-upgrade.md (Nov 15th '18 Protocol Upgrade, bucash 1.5.0.0, 1.5.0.1, 1.5.0.2)

This release also provides an RPC called 'signdata' to generate signatures compatible with the CHECKDATASIG opcode.

Main Changes

• Fix gitian build for macOS
• Improve the script fuzz testing
• In GBT, match fees and sigops with the correct tx
• Improve propagation of non-final and too-long-mempool-chain transactions by deferring them until the relevant block arrives
• New RPC: signdata to generate signatures compatible with the CHECKDATASIG opcode
• Improve documentation (docker, SV activation)