Prevent unneeded mimic compilation in dev_setup.sh
Prevent unneeded mimic compilation in dev_setup.sh

The code that detected existing mimic installs and asked for
confirmation before rebuilding had a few holes:
* A source install of mimic under the mycroft-core tree was missed
* Hitting "enter" or "spacebar" would be interpreted as "yes, rebuild",
  which didn't match the prompt.

aatchison/mycroft-core,aatchison/mycroft-core,MycroftAI/mycroft-core,forslund/mycroft-core,linuxipho/mycroft-core,linuxipho/mycroft-core,Dark5ide/mycroft-core,Dark5ide/mycroft-core,forslund/mycroft-core,MycroftAI/mycroft-core