Splits HAL Digital and Analog Headers into multiple headers (#52)

The Digital and Analog headers (and the implementations, but that will
be moved over later) are just too big and congested. This splits those
headers, and then changes the few things that needed to be changed in
WPILib to get the code working again. No function changes were made in
this commit.

hal/include/HAL/AnalogTrigger.h

@@ -0,0 +1,28 @@
+#pragma once
+#include <stdint.h>
+
+enum AnalogTriggerType {
+  kInWindow = 0,
+  kState = 1,
+  kRisingPulse = 2,
+  kFallingPulse = 3
+};
+
+extern "C" {
+void* initializeAnalogTrigger(void* port_pointer, uint32_t* index,
+                              int32_t* status);
+void cleanAnalogTrigger(void* analog_trigger_pointer, int32_t* status);
+void setAnalogTriggerLimitsRaw(void* analog_trigger_pointer, int32_t lower,
+                               int32_t upper, int32_t* status);
+void setAnalogTriggerLimitsVoltage(void* analog_trigger_pointer, double lower,
+                                   double upper, int32_t* status);
+void setAnalogTriggerAveraged(void* analog_trigger_pointer,
+                              bool useAveragedValue, int32_t* status);
+void setAnalogTriggerFiltered(void* analog_trigger_pointer,
+                              bool useFilteredValue, int32_t* status);
+bool getAnalogTriggerInWindow(void* analog_trigger_pointer, int32_t* status);
+bool getAnalogTriggerTriggerState(void* analog_trigger_pointer,
+                                  int32_t* status);
+bool getAnalogTriggerOutput(void* analog_trigger_pointer,
+                            AnalogTriggerType type, int32_t* status);
+}