Squashed 'underscore/' content from commit ff32da2

git-subtree-dir: underscore
git-subtree-split: ff32da25c2bf0a6ea1a8e9b7bda3651b1de601c2
[underscore] initial import
[rpm] cutes-underscore-js package

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[tests] run test when building package

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[test] adding subprocess tests

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
compress docs

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[debug] use CUTES_DEBUG environment variable to control tracing

CUTES_DEBUG is [0, 5]
// debug : 1, info : 2, warning : 3,
// error : 4, critical : 5
default level is error

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[functional] visit()

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
cutes version dep

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>