Remove GPL license

The MIT license is GPL-compatible anyway, as per @sindresorhus. Ref. https://github.com/mathiasbynens/dotfiles/commit/a89e2f2d226de274c998b0b8de5fd4af2e0b444f#commitcomment-3485954.
bootstrap.sh: Avoid `source` if there are no changes

Closes #220.
.aliases: Make Grunt print stack traces by default
README: Tweak Git-free install command
bin: Update `subl` symlink to `Sublime Text 3.app`
.osx: Add Spotlight settings

Closes #91 and #174.
.bash_profile: Remove ‘autocomplete Grunt commands’

Closes #224.
.brew: Install PHP 5.5
.gitattributes: Disable normalizing line endings globally

Instead of removing `~/.gitattributes` completely, I decided to just comment out the `* text=auto` line. This makes it easier to temporarily re-enable the setting should I ever want to.

Closes #149.
.curlrc: Disguise as IE 9 on Windows 7

This matches the `.wgetrc` settings.
.aliases: Add `timer`

`timer` can be used as a stopwatch.

Hat tip: https://twitter.com/tow8ie/status/360077953238962176
.gitconfig: Improve display of astral Unicode symbols in diffs

Thanks to @holman for the tip: https://speakerdeck.com/holman/more-git-and-github-secrets?slide=38
.osx: Add GPGMail 2 settings

http://support.gpgtools.org/kb/faq-gpgmail/gpgmail-2-hidden-settings
.osx: Disable the sound effects on boot
.aliases: Add `-F` to `ls` aliases

Don’t do this for the default `ls`, though.

Closes #234.
bin: Point `subl` to the default ST3 location

Sublime Text 3 does not use the `/Application/Sublime Text 3.app` folder by default. It uses `/Application/Sublime Text.app`.

Closes #232.
.gitconfig: Remove global remote branch

This causes duplicate remotes to be created, potentially leading Git to throw errors when `push`ing.

Closes #215.
.aliases: Add `chromekill` to kill all Chrome tabs to free up memory

Useful when you have a lot of tabs open (which I always do), but you don’t want to close them.

Tabs in Chrome are just processes, so we just filter out the ones we want, and kill them.

Closes #236.
.osx: `~/.CFUserTextEncoding` can break several Adobe apps

Ref. #237.
.gitconfig: Add comment about `color.ui` in Git ≥ 1.8.4

Ref. #239.