Allow user to import all components at once (#29)

with `from guipy.components import *`

guipy/components/__init__.py

@@ -0,0 +1,19 @@
+import importlib
+import pkgutil
+from inspect import isclass
+
+__all__ = []
+
+# modified from: https://julienharbulot.com/python-dynamical-import.html
+# iterate through the modules in the current package
+# package_dir = Path(__file__).resolve().parent
+for (_, module_name, _) in pkgutil.iter_modules(__path__):
+
+    # import the module and iterate through its attributes
+    module = importlib.import_module(f"{__name__}.{module_name}")
+    for attribute_name in dir(module):
+        attribute = getattr(module, attribute_name)
+        if isclass(attribute):
+            # Add the class to this package's variables
+            globals()[attribute_name] = attribute
+            __all__.append(attribute_name)