Exclude ~/.m2

[domkm]

We ran into Heroku slug size issues but the current exclude-m2 branch is broken and, since it is conditional exclusion, it might make sense for the feature to be in master.

Based on fdc6c89 and #7

[paxan]

Does this mean that when /app/.m2 is missing in the slug, your boot-clj Heroku app will commence to download Maven artifacts at every deploy, restart, and so on?

If I remember right, Heroku has a limit on how long the app can take before it binds to PORT. I've ran into issues before when the app takes too long to boot because it was bootstrapping itself for too long.

[paxan]

@domkm, I've just realized that it depends on what you do at build time! E.g. if you build an uberjar, then /app/.m2 is entirely useless.