undid changes + put ftdi & serial behind features

- serial_comm and ftdi_comm features added
- received/recieved typos reverted for inclusion in another PR
- fuel_level change reverted for inclusion in another PR
- DeviceError's 0 field made private again

Cargo.toml

@@ -8,7 +8,11 @@ edition = "2021"
 
 [dependencies]
 env_logger = "0.10"
-ftdi = "0.1.3"
 log = "0.4.8"
 thiserror = "1.0.15"
-serialport="=4.6.1"
+ftdi = { version = "0.1.3", optional = true }
+serialport= { version = "=4.6.1", optional = true }
+
+[features]
+ftdi_comm = [ "dep:ftdi" ]
+serialport_comm = [ "dep:serialport" ]