Fix command listing to work on pip package installs

bin/etherpump

@@ -1,36 +1,46 @@
 #!/usr/bin/env python3
 
-import os
 import sys
-from importlib import import_module
-from pathlib import Path
 
 from etherpump import __VERSION__
 
 
 def subcommands():
     """List all sub-commands for the `--help` output."""
-    not_sub_commands = ['common.py', 'appendmeta.py', 'html5tidy.py', 'join.py']
-    subcommands = []
-
-    all_files = os.listdir(Path().absolute() / 'etherpump' / 'commands')
-    modules = filter(
-        lambda file: not file.startswith('__')
-        and not any(file == module for module in not_sub_commands),
-        all_files,
-    )
-
-    for module in modules:
-        name = module.split('.py')[0]
+    output = []
+
+    subcommands = [
+        'creatediffhtml',
+        'deletepad',
+        'dumpcsv',
+        'gethtml',
+        'gettext',
+        'index',
+        'init',
+        'list',
+        'listauthors',
+        'publication',
+        'pull',
+        'revisionscount',
+        'sethtml',
+        'settext',
+        'showmeta',
+    ]
+
+    for subcommand in subcommands:
         try:
-            doc = import_module(f'etherpump.commands.{name}').__doc__
+            # http://stackoverflow.com/questions/301134/dynamic-module-import-in-python
+            doc = __import__(
+                "etherpump.commands.%s" % subcommand,
+                fromlist=["etherdump.commands"],
+            ).__doc__
         except ModuleNotFoundError:
             doc = ""
-        subcommands.append(f'    {name}: {doc}')
+        output.append(f'    {subcommand}: {doc}')
 
-    subcommands.sort()
+    output.sort()
 
-    return '\n'.join(subcommands)
+    return '\n'.join(output)
 
 
 usage = """

setup.py

@@ -48,6 +48,7 @@ setup(
         "python-dateutil",
         "pypandoc",
         "tqdm",
+        "requests",
     ],
     classifiers=[
         'Programming Language :: Python :: 3',