add SetStringFeature to HID library

Author: abratchik

libraries/HID/src/HID.cpp

@@ -140,6 +140,17 @@ int HID_::SetFeature(uint16_t id, const void* data, int len)
     return reportCount;
 }
 
+int HID_::SetStringFeature(uint8_t id, const uint8_t* index, const char* data) {
+    
+    int res = SetFeature(id, index, 1);
+    
+    if(res == 0) return 0;
+    
+    res += SetFeature(0xFF00 | *index , data, strlen_P(data));
+    
+    return res;    
+}
+
 bool HID_::LockFeature(uint16_t id, bool lock) {
     if(rootReport) {
         HIDReport* current;

libraries/HID/src/HID.h

@@ -117,6 +117,7 @@ class HID_ : public PluggableUSBModule
     int begin(void);
     int SendReport(uint16_t id, const void* data, int len);
     int SetFeature(uint16_t id, const void* data, int len);
+    int SetStringFeature(uint8_t id, const uint8_t* index, const char* data);
     bool LockFeature(uint16_t id, bool lock);
 
     void AppendDescriptor(HIDSubDescriptor* node);