v0.7.1

ChainRulesCore v0.7.1

Diff since v0.7.0

Merged pull requests:

• Add ChainRulesTestUtils to FAQ (#125) (@nickrobinson251)
• Sort out frule API (#129) (@willtebbutt)
• Allow failures on 1.4 (#130) (@oxinabox)
• Fix doctests; Organise and improve some docs (#131) (@nickrobinson251)
• Fix docs page xref (#132) (@nickrobinson251)
• More xrefs (#133) (@nickrobinson251)
• Remove line about no tests (#134) (@nickrobinson251)
• Export AbstractThunk (#135) (@nickrobinson251)