title: Match with OR condition
body: <p>been playing around with cypher for a while now and having a bit of difficulty understanding something.</p>
  
  <p>assuming i have person nodes some of which might have a belongs_to relationship 
  what would be the best way to find a node that either </p>
  
  <ul>
  <li>does <strong>not</strong> have a blongs_to relationship but does have an email address
  of "x@x.xom"   </li>
  <li>OR</li>
  <li>does have a belongs_to relationship with a Id Property of "100" ( the property is of the relationship) </li>
  </ul>
  
  <p>i have managed to create some queries that return the expected data, but i don't know if those are ones that are "correct" in the long run of my cypher understanding </p>
  
  <p>any help would be appreciated.  ( specifically with regards to And | Or , order and efficiency )</p>