Add PATH caveats to MacTeX Cask

Warns user that they may need to add the mactex `/usr/texbin` directory to their
PATH manually, as the package does not seem to do this or symlink automatically.

Fixes #2277.

See also [this comment](https://github.com/phinze/homebrew-cask/pull/2284#commitcomment-4974770)
on #2284 for more information.
Add Sonic Visualiser cask formula
fix test cruft introduced by #2304
Distinguish between checking SHA-1 & SHA-256 sums

A couple casks use SHA-256 checksums. Add language to describe how to
determine those checksums in an easy way.
XBMC Update from 12.2 to 12.3

Updating cask to pull latest version of XBMC (12.3).
Merge pull request #2309 from j9ac9k/xbmc

XBMC Update from 12.2 to 12.3
Merge pull request #2308 from goxberry/contributing-sha256

Distinguish between checking SHA-1 & SHA-256 sums
Merge pull request #2307 from rolandwalker/shutup_uri_tests

fix test cruft introduced by #2304
Add cask for Amazon Cloud Player
Merge pull request #2306 from finitum/sonic-visualiser

Add Sonic Visualiser cask
Merge pull request #2313 from kevinSuttle/amazon-cloud-player

Add cask for Amazon Cloud Player
Merge pull request #2284 from colindean/patch-1

Add PATH caveats to MacTeX Cask
Wireshark 1.10.5

Fixes #2288
fix dbeaver link path
Mactracker update from 7.2.1 to 7.2.3
Merge pull request #2315 from kols/mactracker

Mactracker 7.2.3
OpenEmu update from 1.0 to 1.0.1
Merge pull request #2316 from kols/openemu

OpenEmu update from 1.0 to 1.0.1
Gimp 2.8.10->2.8.10p2; fixes nasty outline bug
Add cask for Tomighty