clang-tidy: range for loop conversions

Found with modernize-loop-convert

Ran through git clang-format.

Also removed several questionable loops and replaced with simpler
algorithms.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

samples/exifdata.cpp

@@ -35,19 +35,15 @@ void syntax(const char* argv[],format_t& formats)
 	std::cout << "Usage: " << argv[0] << " file format" << std::endl;
 	int count = 0;
 	std::cout << "formats: ";
-	for ( format_i i = formats.begin() ; i != formats.end() ; i++ ) {
-		std::cout << ( count++ ? " | " : "") << i->first ;
-	}
-	std::cout << std::endl;
+    for (auto&& format : formats) {
+        std::cout << (count++ ? " | " : "") << format.first;
+    }
+    std::cout << std::endl;
 }
 
 size_t formatInit(Exiv2::ExifData& exifData)
 {
-	size_t result = 0;
-	for (auto i = exifData.begin(); i != exifData.end() ; ++i) {
-		result ++ ;
-	}
-	return result ;
+    return std::distance(exifData.begin(), exifData.end());
 }
 
 ///////////////////////////////////////////////////////////////////////
@@ -59,12 +55,13 @@ std::string escapeCSV(Exiv2::ExifData::const_iterator  it,bool bValue)
 	if ( bValue ) os << it->value() ; else os << it->key() ;
 
 	std::string s = os.str();
-	for ( size_t i = 0 ;i < s.length() ; i ++ ) {
-		if ( s[i] == ',' ) result += '\\';
-		result += s[i];
-	}
+    for (auto&& c : s) {
+        if (c == ',')
+            result += '\\';
+        result += c;
+    }
 
-	return result ;
+    return result;
 }
 
 std::string formatCSV(Exiv2::ExifData& exifData)
@@ -109,13 +106,14 @@ std::string escapeJSON(Exiv2::ExifData::const_iterator  it,bool bValue=true)
 	if ( bValue ) os << it->value() ; else os << it->key() ;
 
 	std::string s = os.str();
-	for ( size_t i = 0 ;i < s.length() ; i ++ ) {
-		if ( s[i] == '"' ) result += "\\\"";
-		result += s[i];
-	}
+    for (auto&& c : s) {
+        if (c == '"')
+            result += "\\\"";
+        result += c;
+    }
 
-	std::string q = "\"";
-	return q + result + q ;
+    std::string q = "\"";
+    return q + result + q;
 }
 
 std::string formatJSON(Exiv2::ExifData& exifData)
@@ -141,13 +139,15 @@ std::string escapeXML(Exiv2::ExifData::const_iterator  it,bool bValue=true)
 	if ( bValue ) os << it->value() ; else os << it->key() ;
 
 	std::string s = os.str();
-	for ( size_t i = 0 ;i < s.length() ; i ++ ) {
-		if ( s[i] == '<' ) result += "&lg;";
-		if ( s[i] == '>' ) result += "&gt;";
-		result += s[i];
-	}
+    for (auto&& c : s) {
+        if (c == '<')
+            result += "&lg;";
+        if (c == '>')
+            result += "&gt;";
+        result += c;
+    }
 
-	return result ;
+    return result;
 }
 
 std::string formatXML(Exiv2::ExifData& exifData)