CSS: attribute selectors: fix parsing of case insensitive flag

The ' i' flag should be outside the parenthesis with the attribute
value:
div[foo="bar i"] should not match foo="bar" nor foo="BAR", but
only foo="bar i".

Also, "div[foo=], blockquote {...}" is invalid and should make
the whole declaration discarded (including the blockquote).

crengine/src/lvstsheet.cpp

@@ -2871,16 +2871,18 @@ bool parse_attr_value( const char * &str, char * buf, bool &parse_trailing_i, ch
         buf[pos] = 0;
         str += pos+1;
         skip_spaces( str );
-        if (*str != stop_char)
-            return false;
-        str++;
-        if (parse_trailing_i && pos >=2) {
+        // The trailing ' i' must be outside the quotes
+        if (parse_trailing_i) {
             parse_trailing_i = false;
-            if ( (buf[pos-2]==' ') && (buf[pos-1]=='i' || buf[pos-1]=='I') ) {
+            if (*str == 'i' || *str == 'I') {
                 parse_trailing_i = true;
-                buf[pos-2] = 0;
+                str++;
+                skip_spaces( str );
             }
         }
+        if (*str != stop_char)
+            return false;
+        str++;
         return true;
     }
     else
@@ -2893,6 +2895,8 @@ bool parse_attr_value( const char * &str, char * buf, bool &parse_trailing_i, ch
         int end_pos = pos;
         if (parse_trailing_i) {
             parse_trailing_i = false;
+            if (end_pos == 0) // Empty value, or some leading space: this is invalid
+                return false;
             if (str[pos] && str[pos]==' ' && str[pos+1] && (str[pos+1]=='i' || str[pos+1]=='I')) {
                 parse_trailing_i = true;
                 pos+=2;