Clean up header dependencies

A lot of source files were depending on utils.h being included by other headers
Cleaned up code that was depending on Input.h being included in Pi.h

src/GasGiant.cpp

@@ -11,12 +11,13 @@
 #include "graphics/Frustum.h"
 #include "graphics/Graphics.h"
 #include "graphics/Material.h"
-#include "graphics/Renderer.h"
 #include "graphics/RenderState.h"
+#include "graphics/Renderer.h"
 #include "graphics/Texture.h"
 #include "graphics/VertexArray.h"
 #include "graphics/opengl/GenGasGiantColourMaterial.h"
 #include "perlin.h"
+#include "utils.h"
 #include "vcacheopt/vcacheopt.h"
 
 RefCountedPtr<GasPatchContext> GasGiant::s_patchContext;

src/GeoPatchContext.cpp

@@ -6,6 +6,7 @@
 #include "Pi.h"
 #include "graphics/Graphics.h"
 #include "graphics/Renderer.h"
+#include "utils.h"
 
 #include "perlin.h"
 #include "vcacheopt/vcacheopt.h"

src/GeoSphere.cpp

@@ -20,6 +20,7 @@
 #include "graphics/TextureBuilder.h"
 #include "graphics/VertexArray.h"
 #include "perlin.h"
+#include "utils.h"
 #include "vcacheopt/vcacheopt.h"
 #include <algorithm>
 #include <deque>

src/KeyBindings.cpp

@@ -3,6 +3,7 @@
 
 #include "KeyBindings.h"
 #include "GameConfig.h"
+#include "Input.h"
 #include "Lang.h"
 #include "Pi.h"
 #include "StringF.h"

src/SectorView.cpp

@@ -6,7 +6,7 @@
 #include "Game.h"
 #include "GameConfig.h"
 #include "GameSaveError.h"
-#include "KeyBindings.h"
+#include "Input.h"
 #include "MathUtil.h"
 #include "Pi.h"
 #include "Player.h"
@@ -22,6 +22,7 @@
 #include "gui/Gui.h"
 #include "lua/LuaConstants.h"
 #include "lua/LuaObject.h"
+#include "utils.h"
 #include <algorithm>
 #include <sstream>
 #include <unordered_set>

src/SystemView.cpp

@@ -7,6 +7,7 @@
 #include "Frame.h"
 #include "Game.h"
 #include "GameLog.h"
+#include "Input.h"
 #include "Lang.h"
 #include "Pi.h"
 #include "Player.h"

src/graphics/Graphics.cpp

@@ -7,6 +7,7 @@
 #include "OS.h"
 #include "Renderer.h"
 #include "StringF.h"
+#include "utils.h"
 #include <iterator>
 #include <sstream>
 

src/graphics/opengl/Program.cpp

@@ -7,6 +7,7 @@
 #include "StringF.h"
 #include "StringRange.h"
 #include "graphics/Graphics.h"
+#include "utils.h"
 
 #include <set>
 

src/pigui/PiGui.cpp

@@ -2,9 +2,12 @@
 // Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
 #include "PiGui.h"
+#include "Input.h"
 #include "Pi.h"
+
 #include "graphics/opengl/TextureGL.h" // nasty, usage of GL is implementation specific
 #include "imgui/imgui.h"
+
 // Use GLEW instead of GL3W.
 #define IMGUI_IMPL_OPENGL_LOADER_GLEW 1
 #include "imgui/examples/imgui_impl_opengl3.h"

src/pigui/PiGui.h

@@ -87,6 +87,9 @@ public:
 	// Call at the start of every frame. Calls ImGui::NewFrame() internally.
 	void NewFrame(SDL_Window *window);
 
+	// Call at the end of a frame that you're not going to render the results of
+	void EndFrame();
+
 	// Calls ImGui::EndFrame() internally and does book-keeping before rendering.
 	void Render();
 
@@ -131,8 +134,6 @@ public:
 	static void ThrustIndicator(const std::string &id_string, const ImVec2 &size, const ImVec4 &thrust, const ImVec4 &velocity, const ImVec4 &bg_col, int frame_padding, ImColor vel_fg, ImColor vel_bg, ImColor thrust_fg, ImColor thrust_bg);
 
 private:
-	void EndFrame();
-
 	LuaRef m_handlers;
 	LuaRef m_keys;
 	static std::vector<Graphics::Texture *> m_svg_textures;

src/terrain/TerrainDbg.cpp

@@ -5,6 +5,7 @@
 
 #include "GameConfig.h"
 #include "Pi.h"
+#include "utils.h"
 
 void Terrain::DebugDump() const
 {