[memory] Create new clause

and move [memory], [smartptr], [mem.res], and [allocator.adaptor]
from [utilities] into the new clause.

Author: jensmaurer

source/lib-intro.tex

@@ -29,6 +29,7 @@
 \ref{support}           & Language support library    \\
 \ref{concepts}          & Concepts library            \\
 \ref{diagnostics}       & Diagnostics library         \\
+\ref{memory}            & Memory management library   \\
 \ref{utilities}         & General utilities library   \\
 \ref{strings}           & Strings library             \\
 \ref{containers}        & Containers library          \\