v0.8.54

ApproxFunBase v0.8.54

Diff since v0.8.53

Merged pull requests:

• Parameterize array in InterlaceOperator (#559) (@jishnub)
• Fix cumsum for piecewise spaces (#560) (@jishnub)
• Backport: Fix cumsum for piecewise spaces (#561) (@jishnub)
• Concrete namespace in macros (#562) (@jishnub)
• Backport: concrete namespace in macros (#563) (@jishnub)