parser_util: fix and nitunitfy `parse_something`

Signed-off-by: Jean Privat <jean@pryen.org>
niti: force `eval` to parse things as modules.

Signed-off-by: Jean Privat <jean@pryen.org>
nitunit: allows multiple independant block in a single comment

A new block is started by non-trivial modules

Signed-off-by: Jean Privat <jean@pryen.org>
nitunit: `-W` warns fishy block in comments

Usefull to find buggy nitunit tests with the `--no-act` flag.

Signed-off-by: Jean Privat <jean@pryen.org>
nitunit: keeps track of the source directory of the tested module.

So you can do something like `nitunit src/tests.nit`.
Alternative of #415

Signed-off-by: Jean Privat <jean@pryen.org>
lib: fix some nitunit tests, thanks to the new features of the tool

Signed-off-by: Jean Privat <jean@pryen.org>
tests: update sav/nitunit_args1.res

Signed-off-by: Jean Privat <jean@pryen.org>