Offer-motivated features: :hline defaults, ranged :hpos, @date :days, :bottom none

- @table: a writer's :hline/:vline replaces the default lines; new
  boundary name 'none' removes all lines
- @table: ranged :hpos argument overrides :cell_hpos per cell
  (\multicolumn{1} in tex; positions a colspan anchor's merged cell)
- @date/@datetime: :days offset argument (sks/date/date.py)
- @document: ":bottom none" suppresses the footer (\pagestyle{empty})

Also carries the escape-system generator/renderer fixes, per-cell-range
:format, and uppercase .TTF/.OTF font recognition from klammertext-dev.

mac/.clang-tidy

@@ -0,0 +1,83 @@
+Checks: >
+  *,
+  -boost-*,
+  -fuchsia-*,
+  -google-*,
+  -zircon-*,
+  -abseil-*,
+  -modernize-use-trailing-return-type,
+  -llvmlibc-*,
+  -altera-*,
+  -android-*,
+  -objc-*,
+  -fuchsia-*,
+  -hicpp-*,
+  -misc-*,
+  -performance-*,
+  -portability-*,
+  -readability-*,
+  -bugprone-*,
+  -cert-*,
+  -clang-analyzer-*,
+  -cppcoreguidelines-*,
+  -google-*,
+  -hicpp-*,
+  -llvm-*,
+  -llvmlibc-*,
+  -misc-*,
+  -modernize-*,
+  -performance-*,
+  -portability-*,
+  -readability-*,
+  -zircon-*
+
+WarningsAsErrors: ''
+HeaderFilterRegex: '.*'
+FormatStyle: none
+CheckOptions:
+  - key: readability-identifier-naming.ClassCase
+    value: CamelCase
+  - key: readability-identifier-naming.ClassMemberCase
+    value: camelBack
+  - key: readability-identifier-naming.ConstexprVariableCase
+    value: CamelCase
+  - key: readability-identifier-naming.ConstexprVariablePrefix
+    value: k
+  - key: readability-identifier-naming.EnumCase
+    value: CamelCase
+  - key: readability-identifier-naming.EnumConstantCase
+    value: CamelCase
+  - key: readability-identifier-naming.FunctionCase
+    value: camelBack
+  - key: readability-identifier-naming.GlobalConstantCase
+    value: CamelCase
+  - key: readability-identifier-naming.GlobalConstantPrefix
+    value: k
+  - key: readability-identifier-naming.GlobalVariableCase
+    value: camelBack
+  - key: readability-identifier-naming.GlobalVariablePrefix
+    value: g_
+  - key: readability-identifier-naming.LocalConstantCase
+    value: camelBack
+  - key: readability-identifier-naming.LocalVariableCase
+    value: camelBack
+  - key: readability-identifier-naming.MemberCase
+    value: camelBack
+  - key: readability-identifier-naming.MemberPrefix
+    value: m_
+  - key: readability-identifier-naming.NamespaceCase
+    value: lower_case
+  - key: readability-identifier-naming.PrivateMemberPrefix
+    value: m_
+  - key: readability-identifier-naming.StaticConstantCase
+    value: CamelCase
+  - key: readability-identifier-naming.StaticConstantPrefix
+    value: k
+  - key: readability-identifier-naming.StaticVariableCase
+    value: camelBack
+  - key: readability-identifier-naming.StaticVariablePrefix
+    value: s_
+  - key: readability-identifier-naming.TemplateParameterCase
+    value: CamelCase
+  - key: readability-identifier-naming.VariableCase
+    value: camelBack