v0.9.11

ApproxFunBase v0.9.11

Diff since v0.9.9

Merged pull requests:

• Backport: Fix cumsum for piecewise spaces (#561) (@jishnub)
• Backport: concrete namespace in macros (#563) (@jishnub)
• Move SpecialFunctions to an extension (#564) (@jishnub)
• Move DualNumbers to an extension (#565) (@jishnub)
• Move Statistics to an extension (#566) (@jishnub)
• Revert "Move Statistics to an extension" (#567) (@jishnub)
• Revert "Move DualNumbers to an extension" (#568) (@jishnub)
• Revert "Move SpecialFunctions to an extension" (#569) (@jishnub)
• Fix maximum(abs, ::Fun) (#570) (@jishnub)