Undefined functions because of missing std:: or header. (#295)

* [bcc32 Error] QPDF.cc(375): E2268 Call to undefined function 'atof'
  Full parser context
    QPDF.cc(358): parsing: void QPDF::parse(const char *)

* [bcc32 Error] QPDFTokenizer.cc(183): E2268 Call to undefined function 'strtol'
  Full parser context
    QPDFTokenizer.cc(163): parsing: void QPDFTokenizer::resolveLiteral()

* [bcc32 Error] pdf-split-pages.cc(52): E2268 Call to undefined function 'exit'
  Full parser context
    pdf-split-pages.cc(50): parsing: void usage()

* PR #295: Including "cstdlib" should be replaced with "stdlib.h" to be more consistent. At the same time I changed the order of the surrounding includes to reflect alphabetical order, because at some files this already have been the case.

examples/pdf-split-pages.cc

@@ -8,9 +8,10 @@
 #include <qpdf/QPDFPageDocumentHelper.hh>
 #include <qpdf/QPDFWriter.hh>
 #include <qpdf/QUtil.hh>
-#include <string>
+
 #include <iostream>
-#include <cstdlib>
+#include <stdlib.h>
+#include <string>
 
 static char const* whoami = 0;
 static bool static_id = false;

ispell-words

@@ -400,7 +400,6 @@ cso
 csoe
 css
 cstdio
-cstdlib
 cstr
 cstring
 ctest

libqpdf/Pl_DCT.cc

@@ -2,10 +2,11 @@
 
 #include <qpdf/QUtil.hh>
 #include <qpdf/QTC.hh>
+
 #include <setjmp.h>
-#include <string>
 #include <stdexcept>
-#include <cstdlib>
+#include <stdlib.h>
+#include <string>
 
 #if BITS_IN_JSAMPLE != 8
 # error "qpdf does not support libjpeg built with BITS_IN_JSAMPLE != 8"

libqpdf/QPDF.cc

@@ -4,6 +4,7 @@
 #include <vector>
 #include <map>
 #include <algorithm>
+#include <stdlib.h>
 #include <string.h>
 #include <memory.h>
 

libqpdf/QPDFTokenizer.cc

@@ -10,8 +10,8 @@
 #include <qpdf/QPDFObjectHandle.hh>
 
 #include <stdexcept>
+#include <stdlib.h>
 #include <string.h>
-#include <cstdlib>
 
 static bool is_delimiter(char ch)
 {