Cleanups (#345)

* Mark two functions and one variable static

These are not used or referenced outside the file they are defined in,
so give the compiler a better chance to optimize the code.

* Remove unused global variables

src/input.cpp

@@ -22,12 +22,6 @@
 
 #include "RapiSender.h"
 
-int espflash = 0;
-int espfree = 0;
-
-long current_scale = 0;
-long current_offset = 0;
-
 class InputTask : public MicroTasks::Task
 {
   private:

src/net_manager.cpp

@@ -61,7 +61,7 @@ static bool eth_connected = false;
 // Start Access Point
 // Access point is used for wifi network selection
 // -------------------------------------------------------------------
-void
+static void
 startAP() {
   DBUGLN("Starting AP");
 
@@ -105,7 +105,7 @@ startAP() {
 // -------------------------------------------------------------------
 // Start Client, attempt to connect to Wifi network
 // -------------------------------------------------------------------
-void
+static void
 startClient()
 {
   DEBUG.print("Connecting to SSID: ");

src/ohm.cpp

@@ -15,7 +15,7 @@
 #endif
 
 String ohm_hour = "NotConnected";
-int evse_sleep = 0;
+static int evse_sleep = 0;
 
 static MongooseHttpClient client;