verbose mode output multiline script source and wait list source

[umputun]

This PR clarifies the running script in verbose mode. In addition to the temp script name reporting, which is saying little, it also prints the script itself, i.e.

 [localhost:56404] script: /tmp/.spot/spot-script1960898714
 [localhost:56404]  + #!/bin/sh
 [localhost:56404]  + set -e
 [localhost:56404]  + export foo=$((1 + 2 + 3))
 [localhost:56404]  + export bar=$((4 + 5))
 [localhost:56404]  + export baz=zzzzz
 [localhost:56404]  + ls -laR /tmp
 [localhost:56404]  + du -hcs /srv
 [localhost:56404]  + cat /tmp/conf.yml

All of this affects verbose mode only, for both script and wait command

[coveralls]

Pull Request Test Coverage Report for Build 5117907162

• 68 of 89 (76.4%) changed or added relevant lines in 2 files are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.08%) to 85.162%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/runner/runner.go	9	10	90.0%
pkg/runner/commands.go	59	79	74.68%

Files with Coverage Reduction	New Missed Lines	%
pkg/runner/commands.go	3	78.59%

Totals
Change from base Build 5108824937:	0.08%
Covered Lines:	2267
Relevant Lines:	2662

---

💛 - Coveralls