handle missing field in input file

Abort operations if an episode number or name is missing in one or
all lines of the file.
make sure episode numbers have a minimum of 2 digits
let the class handle all numbers convertions
minor change on cli arguments
change how classes work

add inheritance and modify classes' methods
use mimetypes to sort files
code organization

reduce to one try/except block
code rework

Use list comprehension to sort files in lists for video and
subtitles. Helper function check_mime() use file's mimetype
to put file in the right list.

CSV style file with episodes names and numbers no more.
Only episodes names in file.

Define a function to parse the filename and get the numbers
of the season and episode.

Reworked main loop.
All Episode objects goes into one list.
Lenght of video and subtitle lists is used so all itens can
be processed.

Bug fixes and more organization.
Docstrings instead of comments
Change how season and episode numbers are found

Update regex to find the correct numbers for season and
episode on the filename.
Function returns a tuple with the numbers or a placeholder
if the pair of numbers can't be found.
Standardize how strings are formated
Update readme
Update regex on parse_file() function

Matches the right block of numbers from the filename to guess
the episode information
Bug fixes