examples: fix maps warnings

examples/word_counter/word_counter.v

@@ -17,7 +17,7 @@ fn main() {
 		println('failed to open $path')
 		return
 	}
-	mut m := map[string]int{}
+	mut m := map[string]int
 	for word in contents.to_lower().split(' ') {
 		key := filter_word(word)
 		if key == '' {

vlib/http/http.v

@@ -61,7 +61,7 @@ pub fn new_request(typ, _url, _data string) ?Request {
 		data: data
 		ws_func: 0
 		user_ptr: 0
-		headers: map[string]string{} 
+		headers: map[string]string
 	}
 }
 
@@ -112,7 +112,7 @@ pub fn (req &Request) do() Response {
 }
 
 fn parse_response(resp string) Response {
-	mut headers := map[string]string{}
+	mut headers := map[string]string
 	first_header := resp.all_before('\n') 
 	mut status_code := 0 
 	if first_header.contains('HTTP/') {

vlib/net/urllib/values.v

@@ -27,7 +27,7 @@ mut:
 // values.encode() will return the encoded data
 pub fn new_values() Values {
 	return Values{
-		data: map[string]Value{}
+		data: map[string]Value
 	}
 }
 

vlib/vweb/vweb.v

@@ -119,7 +119,7 @@ pub fn run<T>(port int) {
 			action = 'index' 
 		} 
 		req := http.Request{
-				headers: map[string]string{} 
+				headers: map[string]string
 			headers2: headers 
 				ws_func: 0
 				user_ptr: 0
@@ -131,9 +131,9 @@ pub fn run<T>(port int) {
 		app.vweb = Context{
 			req: req 
 			conn: conn 
-			form: map[string]string{} 
-			static_files: map[string]string{} 
-			static_mime_types: map[string]string{}
+			form: map[string]string
+			static_files: map[string]string
+			static_mime_types: map[string]string
 		} 
 		//} 
 		if req.method in methods_with_form {