Allow user selected Image save folder

[toonarmycaptain]

• User defined chart save folder
  • subfolders automatically created for each class on class_creation
  • create/check for class_save_folder in default user save folder and create if not present
  • spawn save chart with chart_name and class_save_folder default
  • change to save loc -> save_path/ + classname/ + chartname
• Prompt to select on first run, otherwise default to folder in same folder as app folder
• Add settings option in main menu, with submenu setting to change default image save folder
• Set save folder spawns a GUI directory select
• Remove app_data/image_data folder creation and path in DataFolder and references since it will not be used.
• copy dionysus_charts folder to new location on altered setting
• add tests for this new functionality:

[toonarmycaptain]

GitMate.io thinks possibly related issues are #84 (Make chart images save in correct folder.), #67 (Make avatar images save in correct folder. ), #17 (Logic for image generation), and #33 (Take avatar images and process them).

[toonarmycaptain]

Remove app_data/image_data folder since it will not be used.

[toonarmycaptain]

Complete: Issue appeared with JSON:

Initial test failed on mirrored convert_to_json data:

json_data_to_convert = '{\n    "1": "a",\n    "b": 2,\n    "3": "c",\n    "d": 4\n}'
converted_json_data = {1: 'a', 'b': 2, 3: 'c', 'd': 4}

This is because JSON does not have integer dict keys, so it converts the
integer keys to strings. When loading from JSON, json.loads does not
differentiate between dict keys of stings containing integers and
keys of integers converted to strings when converted to JSON.
Thus the test data was modified to expect strings in test of integers
as dict keys: {"1": 'a', 'b': 2, "3": 'c', 'd': 4}.

So test runs as:

json_data_to_convert = '{\n    "1": "a",\n    "b": 2,\n    "3": "c",\n    "d": 4\n}'
converted_json_data = {"1": 'a', 'b': 2, "3": 'c', 'd': 4}

assert load_from_json(json_data_to_convert) == converted_json_data

Added notes to file_functions.py functions convert_to_json,
load_from_json, in create_chart.py to write_chart_data_to_file, and in
class_functions.py to write_classlist_to_file describing this behaviour,
as it will be an issue if and when chart_data_files are reloaded, since
the keys in score-avatar_dicts are float values which are converted to
strings when converted to JSON, and this will need to be handled.

Handling will probably be as simple as
original_score_avatar_dict = {float(score): avatar_list for score, avatar_list in dejsonified_score_avatar_dict.items()}