renamed line_cap::butt to line_cap::none. It's clearer and will help me avoid accidental infamy/notoriety.

Author: mikebmcl

source/line-cap.tex

@@ -14,7 +14,7 @@
 \begin{codeblock}
 namespace std { namespace experimental { namespace io2d { inline namespace v1 {
   enum class line_cap {
-    butt,
+    none,
     round,
     square
   };
@@ -36,7 +36,7 @@
  & \rhdr{Meaning}
  \\ \capsep
  \endhead
- \tcode{butt}
+ \tcode{none}
  & The line has no cap. It terminates exactly at the end \tcode{point}.
  \\
  \tcode{round}

source/surface.tex

@@ -267,7 +267,7 @@
 \pnum
 After all paths in the path group have been rendered but before the rendered result is composed to the \underlyingsurface, the rendered result shall be transformed from the User Coordinate Space (\ref{surface.coordinatespaces}) to the Surface Coordinate Space (\ref{surface.coordinatespaces}).
 \enterexample
-If an open path consisting solely of a vertical line from \tcode{vector_2d(20.0, 20.0)} to \tcode{vector_2d(20.0, 60.0)} is to be composed to the \underlyingsurface, the Line Cap is \tcode{line_cap::butt}, the Line Width is \tcode{12.0}, and the Transformation Matrix is \tcode{matrix_2d::init_scale(0.5, 1.0)}, then the line will end up being composed within the area \tcode{rectangle( \{ 7.0, 20.0 \}, \{ 13.0, 60.0 \} )} on the \underlyingsurface. The Transformation Matrix causes the center of the \xaxis of the line to move from \tcode{20.0} to \tcode{10.0} and then causes the horizontal width of the line to be reduced from \tcode{12.0} to \tcode{6.0}.
+If an open path consisting solely of a vertical line from \tcode{vector_2d(20.0, 20.0)} to \tcode{vector_2d(20.0, 60.0)} is to be composed to the \underlyingsurface, the Line Cap is \tcode{line_cap::none}, the Line Width is \tcode{12.0}, and the Transformation Matrix is \tcode{matrix_2d::init_scale(0.5, 1.0)}, then the line will end up being composed within the area \tcode{rectangle( \{ 7.0, 20.0 \}, \{ 13.0, 60.0 \} )} on the \underlyingsurface. The Transformation Matrix causes the center of the \xaxis of the line to move from \tcode{20.0} to \tcode{10.0} and then causes the horizontal width of the line to be reduced from \tcode{12.0} to \tcode{6.0}.
 \exitexample
 
 \rSec1 [surface.masking] {\tcode{surface} masking}