Make installation more robust

[yaxu]

There are hopefully improvements with the latest script but still getting reports of problems, lets use this thread to field them

[yaxu]

A helpful report from George Profenza:

I've setup a quick test last night using the MacOS instructions (https://tidalcycles.org/index.php/MacOS_installation)

I hit on a few snags, but not Tidal related per-se:

• SuperCollider 3.10.3 (latest) - signed didn't work on my machine, but that's because I'm on 10.11 and it is compiled with the 10.12 OSX SDK

  (/Applications/Audio/SuperCollider/SuperCollider.app/Contents/MacOS/./SuperCollider 
  dyld: Symbol not found: _kSecKeyAlgorithmECDSASignatureDigestX962SHA1
  Referenced from: /Applications/Audio/SuperCollider/SuperCollider.app/Contents/MacOS/./../Frameworks/QtWebEngineCore.framework/Versions/5/QtWebEngineCore (which was built for Mac OS X 10.12)
  Expected in: /System/Library/Frameworks/Security.framework/Versions/A/Security
  in /Applications/Audio/SuperCollider/SuperCollider.app/Contents/MacOS/./../Frameworks/QtWebEngineCore.framework/Versions/5/QtWebEngineCore
  Trace/BPT trap: 5
  )

• SuperCollider 3.7.2 worked just fine
• silly me forgot I had BT headphones on, which with a crap sampling rate (8KHz instead of 44.1KHz):

  
  (*** Welcome to SuperCollider 3.7.2. *** For help press Cmd-D.
  booting 57110
  -> SuperDirt
  Number of Devices: 7
  0 : "WH-CH500"
  1 : "WH-CH500"
  2 : "Built-in Microph"
  3 : "Built-in Output"
  4 : "Soundflower (2ch)"
  5 : "Soundflower (64ch)"
  6 : "Multi-Output Device"

input and output sample rates do not match. 8000 != 44100 could not initialize audio. RESULT = 1 ERROR: server failed to start For advice: [http://supercollider.sf.net/wiki/index.php/ERROR:_server_failed_to_start]) - switched back to laptop speakers to test

- I must've botched something in SC because I got this error: no synth or sample named 'sn' could be found. 
(maybe I accidentally interrupted the install process and 'sn' didn't make it ?)

I've changed the sn with other vowels and SC was happy.

For reference:
http://sensori.al/yaxu/tidal-osx-install.txt
http://sensori.al/yaxu/super-collider-output.txt