text: Title: Feature request: Check for AVX instruction set during install
  Body: As of late last year TensorFlow requires the CPU to support the AVX instruction set. This is therefore required by the Precise wake word engine. 
  
  Currently there are no checks or warnings when installing Mycroft to indicate that this will be a problem. However a number of users have reported Precise failing and in the end it was identified that they were running on older or lower end hardware.
  
  Mycroft could still be used with PocketSphinx as the wake word engine, however it would be better to notify the user such that they are a) aware of the reduced capability; and b) can choose whether or not to continue.
  
  Advanced users may opt to build an older version of TensorFlow (v1.13) from source. 
  
  The simplest method (that I know of) to identify if AVX is supported is to check for avx in the cpuinfo flags eg:
  `grep avx /proc/cpuinfo`
  
  ### Success criteria
  - During installation CPUinfo is checked to confirm AVX support
  - If available, installation silently continues
  - If unavailable, information is provided to the user and the installation may be aborted
  - If the user opts to continue installation, the PocketSphinx listener should be selected.