Xontrib-pipeliner

Github Actions bump

Fix dependency

Added exception processing in `ppl`

Added showing the line that rises exception to `pl`:
bash
$ echo "1;2\n3;4\nqwe" > test.txt

$ cat test.txt
1;2
3;4
qwe

$ cat test.txt | pl "line.split(';')[1]"
IndexError: list index out of range
2
4
Error line 3: qwe

Fixed multicore context

* Added multicore pipelining with `ppl` command
* Fix import modules before using pipeliner