Create a single executable build of Core for macOS

[larrysalibra]

It should include

• its own python interpreter
• all dependencies
• any required native libraries

It should be relocatable and able to work in any arbitrary directory (including those with spaces).

The objective is to distribute it inside the Blockstack.app application bundle so we can stop extracting a virtualenv to /tmp and so we can properly codesign Core.

We use nexe to do this for node.js code.

pyinstaller http://www.pyinstaller.org is a similar tool for python.

[larrysalibra]

@jcnelson let me know if you need any additional information.

[jcnelson]

Thanks; will take a crack on an OS X machine.

[larrysalibra]

We're aiming for a single folder build.

According to @kantai currently a build with only api service endpoint works.

The plan is to include a full node + integration tests with the idea that in the future we will make regtest a click to enable feature.

We'll push integration of this off until it's ready.

[larrysalibra]

This still needs to be done. We haven't had the bandwidth to work on it.

[larrysalibra]

We'll still need this for bundling core so that users can easily enable a full core node, but this is lower priority now that they dont need a local core node to use the system.