Include lapack dependency, as the new OpenBLAS package no longer bundles LAPACK with itself.
Don't download/install patchelf if it is runnable from $PATH, and install/use it on Travis!
Add USE_SYSTEM_OPENLIBM, enable building of Julia with distribution-provided openlibm
Include openlibm packages in .travis.yml
Updates docs for publishing packages

Instructions to ensure that METADATA is up-to-date before registering a
new package.
Merge pull request #2769 from jiahao/doc-pkg-upd

Updates docs for publishing packages
Merge pull request #2767 from staticfloat/travis

Travis updates
Set: implement using a Dict{K,Nothing} instead of Dict{K,Bool}.

This is Jeff's brilliant idea: since we store Array{Nothing} using
zero space because there's only one possible Nothing value, this is
a way to use the Dict implementation for sets without wasting space
storing the array of values.
fix #2775, restore long versions of command line opts
fix mistake in git example commands