job config requirement elaborated

Rewritten-docs.md

@@ -256,7 +256,11 @@ addons (mostly administrative features).
   workload for administrator (maintain separate installation for every course)
   and high hardware occupation
 - advanced low-level evaluation flow configuration with high-level abstraction
-  layer for ordinary configuration cases
+  layer for ordinary configuration cases; the configuration should be able to
+  express more complicated flows than just compiling a source code and running
+  the program against test inputs -- for example, some exercises need to build
+  the source code with a tool, run some tests, then run the program through
+  another tool and perform additional tests
 - use of modern technologies with state-of-the-art compilers
 
 ### Technical details