[all] Custom functions reworked

[all] Expo function rewritten and many other flash savings (thanks Andreas)
[stock] LONG key press duration is longer
[stock] Rotary Encoder bugs fixed
[stock/gruvin9x] Play Both function added
!!! TRANSLATIONS ALL NEED TO BE UPDATED BEFORE NEXT RELEASE

src/gtests.cpp

@@ -32,6 +32,7 @@
  *
  */
 
+#include <math.h>
 #include <gtest/gtest.h>
 #include "open9x.h"
 
@@ -219,6 +220,8 @@ TEST(EEPROM, rm)
   EXPECT_EQ(sz, 0);
 }
 
+#if defined(FRSKY)
+
 extern void processFrskyPacket(uint8_t *packet);
 
 TEST(FrSky, gpsNfuel)
@@ -266,6 +269,8 @@ TEST(FrSky, dateNtime)
   EXPECT_EQ(frskyData.hub.sec, 50);
 }
 
+#endif
+
 TEST(getSwitch, undefCSW)
 {
   MODEL_RESET();
@@ -425,6 +430,18 @@ TEST(Mixer, RecursiveAddChannel)
   EXPECT_EQ(chans[1], 0);
 }
 
+TEST(Expo, AllValues)
+{
+  // TODO whole range
+  for (uint16_t x=0; x<100; x++) {
+    for (uint16_t k=0; k<100; k++) {
+      // TODO compare with the correct function instead of this one
+      uint16_t ref = ((unsigned long)x*x*x/0x10000*k/(RESXul*RESXul/0x10000) + (RESKul-k)*x+RESKul/2)/RESKul;
+      EXPECT_EQ(expou(x, k), ref);
+    }
+  }
+}
+
 
 int main(int argc, char **argv) {
   StartEepromThread(NULL);