Licensing under MIT
Switched dependencies to git submodules

It is much easier to maintain now as workspace
checkout is tied to Xcode and also is problematic
considering that some files were just aliases
Added simple selection option

useSimpleSelection should be used when multiple selection is required to
avoid user pressing any additional key modifiers
Simple podspec

Unfortunately it requires a dirty workaround: so far CocoaPods uses
submodules correctly while linting but doesn't checkout them while
installing, which fails build. Therefore preinstall script forces
submodules checkout to get correct files.