recast method `destination_path` as `staged_path`

* part of DSL 1.0 review
* `destination_path` was always a bit vague (it refers to
  Cask-specific, version-specific location under
  `/opt/homebrew-cask/Caskroom`)
* here renamed `staged_path` to match upcoming command verb
  `brew cask stage`
* rename also intended to reduce confusion when we implement
  copying as a configurable alternative to symlinking
* transitional `destination_path` methods to remain while
  Casks are converted (this was documented as a part of the
  DSL, and used by 39 Casks in main repo)
* unrelated variables containing "stage" recast for clarity
reuse version in boom-recorder.rb
reuse version in fliquo.rb
reuse version in geneious.rb
reuse version in jabber-video.rb
reuse version in preform.rb
reuse version in sauerbraten.rb
reuse version in slender.rb
Update adobe-air sha256.
Update Airserver to 5.0.7
update for backuploupe and launchcontrol
updated mamp to 3.0.7.1
Merge pull request #6803 from pan-long/update-mamp

updated mamp to 3.0.7.1
Merge pull request #6802 from swayf/somazone_update

update for backuploupe and launchcontrol
Merge pull request #6800 from exherb/airserver-5.0.7

Update Airserver to 5.0.7
Add CausticOSX.app v3.1.0

Closes #6799.
Merge pull request #6798 from hswong3i/adobe-air-sha256

Update adobe-air sha256.
Merge pull request #6806 from vitorgalvao/fix-6799

Add CausticOSX.app v3.1.0
updated scilab to 5.5.1
Update hsang, version 1.2.3.