read_SpikeGadgets_config

  out = read_SpikeGadgets_config(filename)

  Reads the configuration section of a Trodes (.rec) file
  xml header is parsed and read
  out is a 1x1 struct with 12 fields
  configText - length(configText) is the number of characters in header
  filePath               - <--->
  filePrefix             - <--->
  realtimeMode           - logical
  saveDisplayedChanOnly  - logical
  systemTimeAtCreation   - str with systemTimeAtCreation
  timestampAtCreation    - str with timestampAtCreation
  numChannels            - str of number of channels in nTrodes (sum of all trodes channels)
  samplingRate           - str of sampling rate
  headerSize             - str of sum of numBytes in devices / 2
  nTrodes                - struct that lists nTrodes with structs inside that describe each channel
  headerChannels         - channels listed in AuxDisplayConfiguration