Code modernization: subfolders (#6283)

* Code modernization: subfolders

Modernize various code on subfolders client, network, script, threading, unittests, util

* empty function
* default constructor/destructor
* for range-based loops
* use emplace_back instead of push_back
* C++ STL header style
* Make connection.cpp readable in a pointed place + typo

src/util/sha1.cpp

@@ -24,10 +24,10 @@ SOFTWARE.
 
 */
 
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <assert.h>
+#include <cstdio>
+#include <cstring>
+#include <cstdlib>
+#include <cassert>
 
 #include "sha1.h"
 
@@ -96,7 +96,7 @@ void SHA1::process()
 									+(bytes[t*4 + 2] << 8)
 									+ bytes[t*4 + 3];
 	for(; t< 80; t++ ) W[t] = lrot( W[t-3]^W[t-8]^W[t-14]^W[t-16], 1 );
-	
+
 	/* main loop */
 	Uint32 temp;
 	for( t = 0; t < 80; t++ )
@@ -154,7 +154,7 @@ void SHA1::addBytes( const char* data, int num )
 		num -= toCopy;
 		data += toCopy;
 		unprocessedBytes += toCopy;
-		
+
 		// there is a full block
 		if( unprocessedBytes == 64 ) process();
 	}
@@ -168,7 +168,7 @@ unsigned char* SHA1::getDigest()
 	Uint32 totalBitsH = size >> 29;
 	// add 0x80 to the message
 	addBytes( "\x80", 1 );
-	
+
 	unsigned char footer[64] = {
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,