Fixed a bunch of small errors

_File:
- removed unnecessary documentation at top
- updated __str__

_Thread:
- implemented use of Final_Measurement object

FieldTest_File:
- Fixed issue in parseThreads() where PING tests in netbook files would
not be parsed (“ping” -> “Pinging”)
- updated __str__

Final_Measurement:
Very similar file to _Measurement, only it prints out “Final
Measurement” before the actual measurement

PING_Test:
- updated parent’s __init__ call
- updated __str__

TCP_Test:
- updated parent’s __init__ call
- update error message in case of bad output
- updated __str__

TCP_Thread:
- updated parents __init__ call

UDP_ServerReport:
- updated parents __init__ call
- updated calculation of Dtgrams_Perc
- updated __str__

UDP_Test:
- updated parents __init__ call
- updated __str__

UDP_Thread:
- updated parents __init__ call
- updated __str__

test_parser:
- first line of output file actually contains the original folder path,
not the path of the file itself (d’oh!)