(Feature)|Add support for SwiftPM (#8)

This adds support for SwiftPM 5.3 while also maintaining existing support for Carthage / CocoaPods:
- Source files have been restructured to follow Swift Package guidelines
- Headers have been isolated in order to specify a `publicHeadersPath`. This includes `_Private` and `_Protected` headers, which don't really provide much benefit to begin with
- `NSBundle` resolution attempts to access the generated `SWIFTPM_MODULE_BUNDLE` if it exists, which is necessary for projects that link the target via SwiftPM

(Maint)|Add Carthage support (#6)

* Add Carthage support

- Add shared scheme and an iOS framework target to make this a
framework consumable by Carthage
- Fix broken workspace & project
- Fix broken MBDebugPanelDemo target
- Remove internal cocoapod dependency for itself (for Demo target)
- Fix all build issues
- Reorganize file structure some & remove some stagnant files

* Add 'presentViewController:animated:completion' to public class method declarations

* Cleanup

- Add -setTitle: to MBDebugPanel
- Remove plist files for nonexistent frameworks
- xCode autocorrected some project warnings

Merge pull request #4 from fvasc/bugfix/access-resources-when-loading…

…-pod-as-framework

point to framework bundle

Update Podspec

v0.2.0 Bug fix to simple 'switch' component

Update podspec

linting issues