README: update compilation documentation

Signed-off-by: Max Regan <mgregan2@gmail.com>

README.md

@@ -1,8 +1,28 @@
 A work-in-progress Gameboy emulator with a terminal-based UI and a basic assembler.
 
-== Compilation ==
+## Compilation
+
+```
+make config-release
+make
+```
+
+### Docs
+
+```
+doxygen ./doxygen.config
+```
+
+### Tests
 
 ```
 make config-default
-make
+make check
+```
+
+### Coverage
+
+```
+make config-coverage
+make coverage-report
 ```