Move tests to src/tests directory
Add test_all bash script to run tests in /tests
Fully delete old test files from git

Old tests were still in git, needing to be removed with git rm.

Deleted unnecessary and unhelpful docstring from Prettifying class in
test_amazon_wishlist_tools.py
Move creation of parser into setUp function

This allows the tests to use a new instance of the parser without having
it instantiated in each test
Fix multi-line test string
Add initial tests for get_wishlist.py

Currently gets unicode error from reading example_wish_list.htm, which
needs to be rectified
Remove accidental bracket
Convert example_wish_list to UTF-8

Python was trying to open the ISO-8859-1 encoded htm file as UTF-8
Add second test html file

This file, tests/example_wish_list_2.htm, has two books in the wish
list, and the second has modified priority, number wanted and number
owned.
Add test to test parsing of example_wish_list_2.htm

This should ensure that the parser still works in files with multiple
items in the list, and with different priorities, numbers wanted and
numbers owned