Upgrade MultiBit.app to v0.5.18

Downloaded new release. Verified with GPG key. Hashed with `shasum -a
256`. Tested installation. Audit passed.
Merge pull request #4127 from andschwa/multibit

Upgrade MultiBit.app to v0.5.18
Fix hashcat cask

  * Add missing depends_on_formula 'unar'
  * Discussion: https://github.com/phinze/homebrew-cask/pull/4010
Merge pull request #4135 from craSH/hashcat

Fix hashcat cask
Add Noisy.app v1.5

Noisy is a white/pink/brown noise generator, helpful for concentration.

Changing Noisy.app to use version latest scheme
Merge pull request #4137 from zacs/noisy

Add Noisy.app v1.5