add bar drawing, use pointers more

include/LCDDisplay.hpp

@@ -12,6 +12,9 @@ class LCDDisplay {
     LCDDisplay(std::string dev, uint32_t baud);
     ~LCDDisplay();
 
+    // custom char array
+    char cc[8] = {'\0', '\1', '\2', '\3', '\4', '\5', '\6', '\7'};
+
     void clear();
     void setContrast(uint8_t contrast);
     void setBacklight(bool enabled);
@@ -19,4 +22,5 @@ class LCDDisplay {
     void writeLines(std::array<std::string, 4> lines);
     void writeSStream(std::stringstream& ss);
     void setCustomChar(uint8_t index, std::array<uint8_t, 8> cchar);
+    char bar(uint8_t char_id, double value);
 };