Adding noise rate calc. Continued work on DB access and use

main.py
- better error message w/ traceback

STDS
- added class vars to hold number of files parsed (total, w/ carrier,
w/o)
- moved counting of CPUC files in given folder to data_utils
- made creating TCP Distribution a little more generic (used to get
stdev distrib and noise rate distrib currently)
- new function for converting data structure of noise rates to CSV

SpeedTestFile
- function for calculating TCP Noise Rates added

TCP Test
- fixed issue with getting time intervals of Measurement (use timeEnd,
not secIntervalEnd)

data_utils
- created function that, given a folder directory, counts all of the
files that are CPUC raw data files

DB API
- moved everything into class api()
- - init create dictionary of config information. if pass phrase is
used, uses root login info (stored in db_root_info)
- connect() makes connection to database. Keeps connection object as
object var.
- added semi-private _run_Query() function that runs SQL query given in
function arguments

table_creation.sql
- added bit that creates ‘CPUC_User’ user info if not already created,
and grants necessary privileges.

submain_obj
- reworked option choice. 2 and 3 now go to other “sub” menus, that
take another input (choice of analysis) and pass to STDS function

submain_db
- working on creating similar menu interface to submain_obj
- commented text are tests.