* Switched to lts-8.13, added custom-setup.
Our packages no longer elicit complaints like this:
Package tensorflow-foo uses a custom Cabal build, but does not use a
custom-setup stanza.
* Removed some extra-deps and explicit-setup-deps
* Removed provisions for different versions of stack lts.
We are now solidly in the 8-only territory.
The script can now be run with, e.g.
`env STACK_RESOLVER=lts-7.3 ci_build/outer_launch_tests.sh`
and will use the specified version of the resolver.
We can't quite enable this for lts-7.3 as the code is not pedantically
clean. We will reconsider when 8.0.2 is available which removes
`-Wredundant-constraints` from `-Wall`.
- Uses docker to put everything together.
- stack is running on "raw" system, similar to MacOS build.
- Still not finding libtensorflow_c.so in tensorflow-core-ops setup.
