[util] zip, mapByField, objFromPairs

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[tests] basic initial tests

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[os] environ, mountpoint

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[os] os.path.mime

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[test] throw exception if fixture is failed

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
Merge pull request #2 from deztructor/master

os & util: more functions