Attempt to make README more relevant

- be more specific how to configure and install devstack
 - fix formatting of quark validation to prevent horizontal scrolling
 - be more clear on what local.conf is and where to get more information/clarification about it
 - added Caution to top of README about DevStack and Tempest
 - add info about creating non-root, sudo user and note why we have to use sudo when install aiclib and quark
 - add issue 50 to README to track tempest tests failing
Merge pull request #48 from jmeridth/readme

Attempt to make README more relevant