[dev_setup] Cache Erlang tarballs

  To speed up repeated installation on slow links.

Change-Id: I575c76ff167a07c7174d4893c65a6bbc7b9e559d
[dev_setup] Prettify list of dirs

  Confine the list to column limit of 100.

Change-Id: I0b544f967fcd275f49eb0d531a7ca48e054405f4
[dev_setup] Accept -l for log levels

  Tune out the debug noise when we are allowed.

Change-Id: I9c841ff72127c1b3cc89e562b204ed6ba9b0502a
[dev_setup] Cache ruby tarballs

  Ruby source tarballs are now cached to speed up repeated
installations.
  Test plan: run dev_setup without cache, with cache, and with a
corrupted cached tarball.

Change-Id: I3bd5e089d60ac9b51193f80efffa916d63fdba36
[dev_setup] Cache Node.js tarballs

  Node.js source tarballs are now cached to speed up repeated
installations.
  Test plan: run dev_setup without cache, with cache, and with a
corrupted cached tarball.

Change-Id: Id1b8e3626cd9491cfd26e9b338dbbc75eca742cc
[dev_setup] Use -eq for arithmetic comparison

  Double equal sign is Bashism for String pattern matching. Bang equal
is also for string pattern matching.

Change-Id: Ic5196a098e0cf44c1ed38ddf0ca6f1260bd8a76e
[dev_setup] Install wget

  Wget is not included in `ubuntu-minimal'. Installing wget before
proceeding enables us to run dev_setup in a debootstrap chroot / jail.

Change-Id: Iff012208f58f9946c64ce27448294af42e558a57
[dev_setup] Add key from keyserver

  This removes the dependency of wget on adding Opscode packaging PGP
key.
  This also fixes a bug in previous commit of omitting a space before
the closing bracket.

  Test plan: manually remove the key and apt source and run dev_setup.

Change-Id: I445c62b718373f6da61ca9270b9ee1a04544a53f
[dev_setup] Enforce 2-space indentation

  Formatting change.

Change-Id: Id222e7b3d125c0313dd922378aa3bc20dd78b2cb
[dev_setup] Clear bundler config

  This change clears all bundler remembered settings before attempting
an installation.
  Probably due to the huge repository size, a lot of users try copying
their repos around, despite the recommended best practice of only
copying the bare repo. This change should solve the problem of a
conflict between the dev / test group of gems and production gems for
components, say the Cloud Controller.

  The installer now prompts the user before purging those .bundle
directories, or if you want to run non-interactively, pass --all or -a
to it.

Change-Id: I04b6b9ad462546b51ab1ee11e7e8de91263372bd
[dev_setup] Cache Redis tarballs

  Test plan: run dev_setup with a cached tarball, without one, and with
a corrupt tarball.
  And to pass BVTs, without doubt.

Change-Id: Iefd2172c8966cef08838e70e6207dbb6c39a4fd2
[dev_setup][bugfix] Untar from cache

  This fixes a bug in I575c76ff , I3bd5e089 and Id1b8e362 that tried
decompressing the source tarballs from /tmp instead of the cache
location.

  Test plan: run dev_setup with no cached tarball and no built rubies,
node.js or erlang.

Change-Id: I97d0595bdf3e1f85335a5e8841e28433028219f9
[dev_setup] Do not use rake

  This change removes the assumption that Rake is available at the time
of installation and only uses "find" to remove bundler settings.

  Users can use vcap_dev_setup -a to skip the prompt (DANGEROUS)

Change-Id: Ibbf62b739452abc47709d5cb84e9b620ae1e5b1b