[osx] - move alias/shortcut translation code to darwinhelpers
[osx] - replace alias / shortcut handling with non deprecated functions
(fixes non working alias resolving since osx 10.10 yosemite)
[osx] - add method for creating an alias shortcut (used for unit testing)
[tests/osx] - add unit tests for aliasshortcut resolving
Merge pull request #5934 from Memphiz/osxfixalias

[osx] - replace alias shortcut resolving with non-deprecated API