.functions: Optimize `dataurl`

Thanks to @lri: https://github.com/fin1te/dotfiles/commit/b8ce15ee91bc8658c27599347c376c30c6bfa1e1#commitcomment-1749202
.functions: Add `fs`

…and remove the `fs` alias from `.aliases`.

Ref. #125.
README: Link to @matijs/dotfiles instead of @matijs/homedir
.aliases: Make `flush` kill `mDNSResponder` as well

Ref. #126 and http://support.apple.com/kb/HT5343.
.osx: Add iPhone Simulator.app to Launchpad
.aliases: Remove `ios`
.gitconfig: Add `reb` alias

Stolen from https://github.com/porada/dotfiles/commit/05162b585b2e9cd6a92f12e1c61e1f5687104a17.
.aliases: Add `gurl` for Gzip-enabled `curl`

Ref. 1b3ed7a646de7a652f0596985af976a438e32aca.
.osx: Check for software updates daily
.osx: Enable the WebKit Developer Tools in the Mac App Store

More info here: http://osxdaily.com/2011/09/07/enable-element-inspector-mac-app-store/

Ref. #129.
.functions: Tweak `fs`
.gitconfig: Tweak `diff` aliases
.gitconfig: Explain `diff`-related aliases
.osx: Correct symlink for iOS Simulator

Ref. #135.
.osx: Restart Dashboard
.aliases: Add `dt`
.osx: Consistency tweaks
.aliases: Alias `sha1sum` if needed

Ref. #141.
.aliases: Add `dl`

Ref. #142.
.aliases: Make `update` update Ruby gems as well