Rename the main binary and update the README

- Update the README listing existing macros and how to
  use the renderer.
- Rename the main program to render-test-case
- Rename the tc directory to tests-cases

Signed-off-by: Luis Araujo <luis.araujo@collabora.co.uk>

README.md

 Repository for Apertis tests cases.
 
-# Format Rules/Notes
+## Format Rules/Notes
 
 - Test cases with an `install.deps` directive will automatically add a
   `pre conditions` section to the test case page with the list of packages to
   install specified in such a directive.
+
+## Macro helpers
+
+Some test cases share the same set of instructions, for those, some `macros` are
+available: `macro_ostree_preconditions` , `macro_install_packages_preconditions`,
+and `macro_modules_preconditions`. Please check the tests cases for example about
+how to use them.
+
+## Command
+
+The main program is located inside the `renderer/` subdirectory and can be directly
+invoked from inside that directory:
+
+```
+$ cd renderer/
+$ ./render-test-case --help
+```
+
+The above command will show the help.
+
+To render a single test case, use something like:
+
+```
+$ ./render-test-case ../tests-cases/<test-case-name>.yaml
+```
+
+That will create a `<test-case-name>.html` page.
+
+To render a complete set of test cases inside a directory, just pass a directory
+instead of a file to the command, and optionally pass a new directory path with
+`-d` flag so all the newly generated test cases are saved there instead of the
+current directory:
+
+```
+$ ./render-test-case ../test-cases -d apertis-tests-cases-v0.1/
+```
+
+Now all the tests cases should be available inside the `apertis-tests-cases-v0.1/`
+directory.

renderer/make_page.py → renderer/render-test-case

 #!/usr/bin/env python3
 #
-# Make a web page from a YAML test case file.
+# Create a HTML page from a YAML test case file.
 #
 
 import os