Brewfile: Fix PHP 5.5 installation

Thanks to @interputed for the heads up: https://github.com/mathiasbynens/dotfiles/commit/a76db30d6529e41138009fe3dc67f21ba782496e#commitcomment-6200104
Caskfile: Move `phinze/cask` to `caskroom/cask`

Homebrew Cask has been moved to https://github.com/caskroom/homebrew-cask.

Closes #375.
.gitconfig: Make sure `go` never overrides branches

Closes #357. Thanks to @yukideluxe!
Brewfile: Install `hashpump`
.bash_prompt: Speed up the Git commands for the prompt

Fixes #227 and closes #380.
.bash_profile: Enable tab completion for `git` and `g`

Closes #197.
Brewfile: add instructions on how to change the default shell to Bash 4
Brewfile: Install Node with npm

Ref. https://github.com/Homebrew/homebrew/pull/28075. Closes #362.
bootstrap.sh: Make `rsync` output numbers in a human-readable format

Closes #383.
Brewfile: Install BFG Repo-Cleaner
.curlrc: Set connection timeout to 60 seconds

This matches the setting in `.wgetrc`.
Remove some things that I don’t use

This commit drops some aliases, functions, and settings from the project that I wasn’t using at all. It also cleans up some of the remaining code.
Caskfile: Update Tor formula name

Closes #388.
.gitconfig: Improve configuration

Closes #366.
.osx: Add (commented-out) instructions on how to set the wallpaper

Closes #356.
.osx: Only install custom Terminal profile once

Closes #336 and #337.
.screenrc: Add some more settings

Closes #334.
.osx: Disable the Launchpad gesture

Closes #316.
Brewfile: Install a more recent version of `screen`

Closes #295.
.bash_profile: Enable Bash completion if `/etc/bash_completion` exists too

This is useful on Linux.

Ref. #278.