Overhaul the command line help output.

Use the new rich-click package for nicer formatting.

multiqc/__main__.py

@@ -9,45 +9,20 @@
 """
 
 from __future__ import print_function
-import click
 import pkg_resources
 from . import multiqc
-from .utils import config
 
 
-def modify_usage_error(main_command):
-    """Function to modify the default click error handling.
-    Used here to tell the user about how to find additional help.
-    With thanks to this Stack Overflow answer: http://stackoverflow.com/a/43922088/713980
-    :param main_command: top-level group or command object constructed by click wrapper
-    :return: None
-    """
-
-    def show(self, file=None):
-        if file is None:
-            file = click._compat.get_text_stderr()
-        color = None
-        if self.ctx is not None:
-            color = self.ctx.color
-            click.utils.echo(self.ctx.get_usage() + "\n", file=file, color=color)
-        click.utils.echo(
-            "Error: %s\n\nThis is MultiQC v{}\n\nFor more help, run 'multiqc --help' or visit http://multiqc.info\n".format(
-                config.version
-            )
-            % self.format_message(),
-            file=file,
-            color=color,
-        )
-
-    click.exceptions.UsageError.show = show
-
-
-if __name__ == "__main__" or __name__ == "multiqc.__main__":
+def run_multiqc():
     # Add any extra plugin command line options
     for entry_point in pkg_resources.iter_entry_points("multiqc.cli_options.v1"):
         opt_func = entry_point.load()
         multiqc.run_cli = opt_func(multiqc.run_cli)
-    # Modify the default click error handling
-    modify_usage_error(multiqc.run_cli)
     # Call the main function
     multiqc.run_cli(prog_name="multiqc")
+
+
+# Script is run directly
+# NB: Usually runs with setup.py console_scripts: 'multiqc=multiqc.__main__:run_multiqc'
+if __name__ == "__main__":
+    run_multiqc()