DOC: Add "Integer Type Specifiers" section

Added coding style guidelines for specifying built-in integer types and
integer types from the C library.

Following recent ITK commits, authored by Lee Newberg:

pull request InsightSoftwareConsortium/ITK#3365
commit InsightSoftwareConsortium/ITK@8c2c654
commit InsightSoftwareConsortium/ITK@e03a941
"STYLE: Drop `signed` and `int` from some types"

pull request InsightSoftwareConsortium/ITK#3139
commit InsightSoftwareConsortium/ITK@a812aa3
"STYLE: Change unsigned to unsigned int."

pull request InsightSoftwareConsortium/ITK#3250
commit InsightSoftwareConsortium/ITK@c173dfd
"STYLE: Remove `std::` prefix from types that work without it"

SoftwareGuide/Latex/Appendices/CodingStyleGuide.tex

@@ -1376,6 +1376,21 @@ \subsection{Const Correctness}
 \end{itemize}
 
 
+\subsection{Integer Type Specifiers}
+\label{subsec:IntegerTypeSpecifiers}
+
+Thoughout the code base, the built-in type `unsigned int` is spelled exactly like that:
+"unsigned int" (rather than just "unsigned"). Other built-in integer types should in
+general be specified by their shortest form. For example, "short", "long", and "long long"
+are preferred to "signed short int", "signed long int", and "signed long long int".
+
+Within the `itk` namespace, integer type aliases from C++ Standard headers for C library
+facilities (like `<cstdlib>` and `<cstdint>`) should generally be used without a `std::` prefix.
+For example, "size_t", "int8_t", and "uintmax_t" are preferred to "std::size_t",
+"std::int8_t", and "std::uintmax_t". When using any of those type aliases, the ITK header file
+"itkIntTypes.h" may need to be `#include`d, to ensure that those types are declared within the
+`itk` namespace. 
+
 \section{Namespaces}
 \label{sec:Namespaces}