message: fixed some typos and added additional comments to file_data.py
diff: '''
  -@brief Class to store data from a specific event
  +@brief Class to store data from each specific file_data type
  -@date Created July 2, 2018
  -@author R. Joseph Paetz
  +@date Created July 10, 2019
  +@author Blake A. HarrimanS
  @bug No known bugs
  '''
  from fprime_gds.common.data_types import sys_data
  from fprime.common.models.serialize import time_type
  +#Takes care of the START packets that the file_decoder will receive
  class StartPacketData(sys_data.SysData):
  '''
  The StartPacketData class stores the start packet information
  '''
  -
  + #Initializes the start packet data with all of the necessary information
  def __init__(self, packetType, seqID, size, sourcePath, destPath):
  '''
  Constructor.
  @@ -36,20 +37,12 @@ class StartPacketData(sys_data.SysData):
  self.sourcePath = sourcePath
  self.destPath = destPath
  -
  - def __str__(self):
  - '''
  - Convert the event data to a string
  -
  - Returns:
  - String version of the channel data
  - '''
  - return self.get_str()
  -
  +#Takes care of the DATA packets that the file_decoder will receive
  class DataPacketData(sys_data.SysData):
  '''
  The DataPacketData class stores the data packet information
  '''
  + #Initializes the data packet data with all of the necessary information
  def __init__(self, packetType, seqID, offset, length, dataVar):
  '''
  Constructor.
  @@ -72,10 +65,12 @@ class DataPacketData(sys_data.SysData):
  self.length = length
  self.dataVar = dataVar
  +#Takes care of the END packets that the file_decoder will receive
  class EndPacketData(sys_data.SysData):
  '''
  The EndPacketData class stores the end packet information
  '''
  + #Initializes the end packet data with all of the necessary information
  def __init__(self, packetType, seqID, hashValue):
  '''
  Constructor.
  @@ -94,10 +89,12 @@ class EndPacketData(sys_data.SysData):
  self.seqID = seqID
  self.hashValue = hashValue
  +#Takes care of the CANCEL packets that the file_decoder will receive
  class CancelPacketData(sys_data.SysData):
  '''
  The CancelPacketData class stores the cancel packet information
  '''
  + #Initializes the cancel packet data with all of the necessary information
  def __init__(self, packetType, seqID):
  '''
  Constructor.
  