Change int type specifiers to equivalent types

Replace 'signed int' with 'int', and 'unsigned int' with 'unsigned',
so that .cpp and .h files are consistent, and doxygen doesn't get
confused

Author: John Nonweiler

src/util/options.cpp

@@ -28,13 +28,13 @@ void optionst::set_option(const std::string &option,
 }
 
 void optionst::set_option(const std::string &option,
-                          const signed int value)
+                          const int value)
 {
   set_option(option, std::to_string(value));
 }
 
 void optionst::set_option(const std::string &option,
-                          const unsigned int value)
+                          const unsigned value)
 {
   set_option(option, std::to_string(value));
 }