Be consistent and portable (#!/usr/bin/env sh over #!/bin/sh) with shebangs.
Merge pull request #1512 from gruns/master

Be consistent and portable (#!/usr/bin/env sh over #!/bin/sh) with shebangs.
ibdknox.css: fix tab coloring

To see what this commit does do following:
1. Set editor theme to "ibdknox".
2. In new-dark.css change var-highlight-fg to #0f0. Save new-dark.css.
3. Connect to 'Light Table UI'.
4. Open multiple editors, change content in one of them. Don't save!
5. Switch between editors, notice color changes in tab names.
6. Undo/redo the change introduced by this commit. Goto step 5.
linux_deps.sh: If 'which curl' fails, exit with its return code.
linux_deps.sh: re-use downloaded LightTableLinux*.gz, clojure-plugin

* download LightTableLinux*.tar.gz only if it doesn't exist and always
  verify its sha1 checksum.
* store clojure-plugin as a git-submodule and clone it only once. Then
  update it with git pull --rebase
linux_deps.sh: remove runner/target/lein-light-standalone.jar in the end