Improving test facilities to new format

[phorward]

It might be worth to change the current implementation of testmode:repl tests into a different notation, which can also be used for examples or explanations.

Current notation (Tokay v0.6)

#testmode:repl
print("a")
print("b" Int)
#---
#23
#---
#a
#b23

Improved notation (proposal by this issue):

#testmode:repl
print("a")  # a
print("b" Int)  # b23
#---
#23

The reason for this proposal:

1. Better readability, especially for huger testcases. See dict.tok, for example. It isn't obvious to which input the output lines refer to.
2. Testcases can also be used for documentation, to quickly show which result a given command produces when typed into the REPL

[phorward]

After some further development on Logics and its test suite, it became clearer and more convenient to provide a test-format as described here: https://github.com/viur-framework/logics#shared-test-cases