get rid of piForeach

apply some code analyzer recommendations
ICU flag now check if libicu exists
prepare for more accurate growth of containers (limited PoT, then constantly increase size)

libs/main/system/pisysteminfo.cpp

@@ -175,7 +175,7 @@ PIVector<PISystemInfo::MountInfo> PISystemInfo::mountInfo(bool ignore_cache) {
 	}
 	if (l_df.size_s() < 2) return ret;
 	l_df.pop_front();
-	piForeachC(PIString & s, l_df) {
+	for (const auto & s: l_df) {
 		PIStringList ml(s.replacedAll("  ", " ").split(" "));
 		if (ml.size_s() < 2) continue;
 		if (ml.front() == "none") continue;
@@ -234,17 +234,10 @@ PIString PISystemInfo::machineKey() {
 		PISystemInfo * si = instance();
 		PIByteArray salt;
 		PIString conf = confDir() + "/.pip_machine_salt";
-		if (PIFile::isExists(conf)) {
-			PIFile f(conf, PIIODevice::ReadOnly);
-			f.open();
-			salt = f.readAll();
-		}
+		if (PIFile::isExists(conf)) salt = PIFile::readAll(conf, false);
 		if (salt.size_s() != SALT_SIZE) {
 			salt = generateSalt();
-			PIFile f(conf, PIIODevice::ReadWrite);
-			f.open();
-			f.clear();
-			f.write(salt);
+			PIFile::writeAll(conf, salt);
 		}
 		ret = si->OS_name + "_" + si->architecture + "_" + si->hostname + "_" + salt.toHex();
 	}