This issue addresses:

• do not use dots in MongoDB column names (these are no longer legal in MongoDB 2.6)
• replace them with nested stuctures 'a.b':'foo' -> 'a': { 'b':'foo' }
• associations pointing to composite ids now avoid the nested structure and place the 1st level of columns flat
  e.g. runners:
  Unknown macro: { race_runnerId}

  => runners:

  { firstname: Emmanuel, lastname: Bernard, ranking:0 }
• dots no longer used even in global and collection per association mode