v0.7.69

ApproxFunBase v0.7.69

Diff since v0.7.68

Merged pull requests:

• compact coefficient show for Fun (#371) (@jishnub)
• Use LinearAlgbera.axpy! uniformly (#372) (@jishnub)
• Tests for CachedIterator (#373) (@jishnub)
• Type-stability in 2d tensorizer iteration (#374) (@jishnub)