gsl-lite v1.0.1

Fixes

• Add span<> constructor overloads for span<>::iterator arguments. (fec81ab)
  This improves backward compatibility, since our iterator used to be a pointer in v0.*, which made span{ otherSpan.begin(), 0 } work because we have constructor overloads that accept pointers.
• Add missing alias templates for polyfills. (62afbe9)

Full Changelog: v1.0.0...v1.0.1