Test compatibility for Windows

[unapproachable]

Fix for #101

Okay, this was far more complicated that I initially imagined. I had to borrow from a couple of different ideas from old versions of the code. Opted to branch the execution of exiftool under win32 as a quoted string instead of using shlex.quote because it does more to mangle the names on Windows (see below) than it does to fix them. Non-win32 functionality should remain as before. Also renamed the test image to something acceptable on win32 platform as a valid filename.

C:\>python
Python 3.8.6 (tags/v3.8.6:db45529, Sep 23 2020, 15:52:53) [MSC v.1927 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import shlex
>>> s = shlex.quote("exif's.jpg")
>>> str(s)
'\'exif\'"\'"\'s.jpg\''

Also added a second test to verify the more common scenario of users adding spaces and punctuation to their image filenames.

--Added additional test image
--Corrected failing trailing slash test with Windows specific test

Test run on my Windows machine:

P:\Projects\phockup>pytest
=============================================== test session starts ================================================
platform win32 -- Python 3.8.6, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: P:\Projects\phockup
plugins: hypothesis-6.3.4, mock-3.5.1
collected 49 items

tests\test_date.py ................                                                                           [ 32%]
tests\test_exif.py ....                                                                                       [ 40%]
tests\test_phockup.py .............................                                                           [100%]

=============================================== 49 passed in 15.35s ================================================