Better solution for thread protection

Added thread protection to the URL array when resetting the thread. R…

…EADME example updated with thread instructions for the timer.

README cleanup

Update Package.swift (daniel-pedersen#12)

Merge branch 'release/v1.2.0'

Add v1.1 to history and update example

Fix error logging

Change API to comply with Swift API Design Guidelines

https://swift.org/documentation/api-design-guidelines/

Swift Package Manager support