Fixes tessel/beta#442
firmware for tessel wifi --erase command
updating command to D
changing _erase to _erase_profiles
Merge pull request #144 from tessel/jh-wifi-erase

firmware for tessel wifi --erase command
Merge pull request #137 from tessel/jon-analog-array

Fixes tessel/beta#442
Replace `pushd` with subshells

Default Ubuntu `dash` used by `make` does not have `pushd`.
Update README.md with install instructions simplified from old wiki page
Merge pull request #1 from tessel/km-docs

Update README
Fixes audio recording for lineIn and mic.