Add SwiftLint

• Add SwiftLint
• Add custom rules in SwiftLint yaml
• Conform all files to SwiftLint suggestions

Improvements to initialization, disconnection, and callback structures

Version 0.7.0 introduces several API-breaking changes and improvements:

• Add StartMode to better encapsulate CBCentralManager initialization options
• Add WarningOptions to better encapsulate connect warning options
• Fix handling of expected and unexpected disconnections
• Add disconnect handler to handle auto-reconnect
• Remove all cancellation callbacks; use existing failure blocks and look for BluejayError.cancelled instead if you need to differentiate between a failure caused by cancellation versus a failure caused by other errors
• Return Bluejay Peripheral instead of CBPeripheral for connect, disconnect, and RSSI observer callbacks; so that you don't have to import CoreBluetooth in many of your files anymore, and you can also get a "better/more suitable" peripheral object to work with
• Fix a scan crash caused by not clearing the scan request's global timer
• Remove set privileges on all public Bluejay instance variables; they are all supposed to be read only from the get go, but a few were settable and that was dangerous

Allow throttling the updates on repeated discoveries

• Added an option to scan to change the threshold for ignoring discoveries based on insignificant changes to RSSI

Add warnings to scan against leaving serviceIdentifiers set to `nil` or empty

Added warnings against using scan with serviceIdentifiers set to nil or empty.

More control over auto-reconnect

• Add API to check whether a peripheral is listening to a characteristic
• Allow disabling auto-reconnect when using cancelEverything
• Expose auto-reconnect variable
• Update readme, changelog, and documentation

Fix podspec

v0.6.2

Fix podspec again and bump version

Fix all Xcode 9.3 warnings

v0.6.1

Fix all Xcode 9.3 warnings and bump version

Add stop and extract CoreBluetooth

• Add a new API to allow shutting down Bluejay and transfer the CoreBluetooth manager and delegate to another library or code

Fix accessing of the listen cache

We weren't using the correct key name to access the listen cache, so listen restoration was broken. This should now be fixed.

Fix incorrect connection cancellation

There was a subtle true/false reversal mistake that we didn't catch when bringing in the new error enums. This was causing the second connection request to cancel the first ongoing connection request.