Removes the Boost case_conv.hpp dependency.

This commit removes the `boost/algorithm/string/case_conv.hpp` dependency from the project. It replaces the `boost::to_lower` and `boost::to_upper` functions with custom functions that are locale independent and ASCII deterministic.

src/netbase.cpp

@@ -19,8 +19,6 @@
 #include <fcntl.h>
 #endif
 
-#include <boost/algorithm/string/case_conv.hpp> // for to_lower()
-
 #if !defined(MSG_NOSIGNAL)
 #define MSG_NOSIGNAL 0
 #endif
@@ -37,7 +35,7 @@ static const int SOCKS5_RECV_TIMEOUT = 20 * 1000;
 static std::atomic<bool> interruptSocks5Recv(false);
 
 enum Network ParseNetwork(std::string net) {
-    boost::to_lower(net);
+    Downcase(net);
     if (net == "ipv4") return NET_IPV4;
     if (net == "ipv6") return NET_IPV6;
     if (net == "onion") return NET_ONION;

src/rpc/server.cpp

@@ -16,7 +16,6 @@
 
 #include <boost/bind.hpp>
 #include <boost/signals2/signal.hpp>
-#include <boost/algorithm/string/case_conv.hpp> // for to_upper()
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
 
@@ -192,9 +191,7 @@ std::string CRPCTable::help(const std::string& strCommand, const JSONRPCRequest&
                     if (!category.empty())
                         strRet += "\n";
                     category = pcmd->category;
-                    std::string firstLetter = category.substr(0,1);
-                    boost::to_upper(firstLetter);
-                    strRet += "== " + firstLetter + category.substr(1) + " ==\n";
+                    strRet += "== " + Capitalize(category) + " ==\n";
                 }
             }
             strRet += strHelp + "\n";

test/lint/lint-includes.sh

@@ -47,7 +47,6 @@ fi
 
 EXPECTED_BOOST_INCLUDES=(
     boost/algorithm/string.hpp
-    boost/algorithm/string/case_conv.hpp
     boost/algorithm/string/classification.hpp
     boost/algorithm/string/replace.hpp
     boost/algorithm/string/split.hpp

test/lint/lint-locale-dependence.sh

@@ -11,11 +11,9 @@ KNOWN_VIOLATIONS=(
     "src/dbwrapper.cpp:.*vsnprintf"
     "src/httprpc.cpp.*trim"
     "src/init.cpp:.*atoi"
-    "src/netbase.cpp.*to_lower"
     "src/qt/rpcconsole.cpp:.*atoi"
     "src/qt/rpcconsole.cpp:.*isdigit"
     "src/rest.cpp:.*strtol"
-    "src/rpc/server.cpp.*to_upper"
     "src/test/dbwrapper_tests.cpp:.*snprintf"
     "src/test/getarg_tests.cpp.*split"
     "src/torcontrol.cpp:.*atoi"