[Work in Progress] Migrate to Stack

[clample]

Bead can now be built using stack. First install stack, then run stack setup to download ghc if necessary. The project can then be built using stack build and run using stack exec Bead.

Flags (like Tests, MySQL, SSO) can be passed as follows: stack build --flag Bead:Tests

Not yet done: migrate start-ghci, start-ghci-nosql, ... to use stack ghci

[clample]

travis-test.sh should also be migrated to use the stack command

[clample]

Dockerfile will need to be updated to install stack and also run stack setup. cabal and ghc will no longer need to be installed in the dockerfile, ghc will be installed by stack setup.

travis is pulling the latest docker image, so the travis build will only pass when an updated docker image is pushed.

[andorp]

I need to create a docker image to test this.