Fix various warnings: [-Waddress], [-Wpointer-arith], [-Wwrite-strings], [-Wreturn-local-addr] and more

Fixes the following GCC 5 warnings:
```
core/os/file_access.cpp:49:19: warning: the address of 'FileAccess::create_func' will always evaluate as 'true' [-Waddress]
servers/audio_server.cpp:192:70: warning: comparison with string literal results in unspecified behaviour [-Waddress]

drivers/gles2/rasterizer_storage_gles2.cpp:4095:90: warning: NULL used in arithmetic [-Wpointer-arith]

modules/gdnative/register_types.cpp:237:3: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
platform/android/export/export.cpp:207:1: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]

modules/gdscript/gdscript.h:150:67: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:119:56: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:123:56: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:127:50: warning: returning reference to temporary [-Wreturn-local-addr]
servers/physics_2d/collision_object_2d_sw.h:131:52: warning: returning reference to temporary [-Wreturn-local-addr]

editor/plugins/skeleton_editor_plugin.cpp:34:36: warning: extra tokens at end of #include directive
modules/bullet/bullet_types_converter.cpp:31:9: warning: #pragma once in main file

editor/import/editor_scene_importer_gltf.cpp:1996:51: warning: name lookup of 'i' changed
modules/visual_script/visual_script_property_selector.cpp:402:45: warning: name lookup of 'E' changed
scene/gui/tree.cpp:1268:25: warning: name lookup of 'i' changed
scene/resources/visual_shader.cpp:808:32: warning: name lookup of 'i' changed
```

1 files changed, 8 insertions, 8 deletions

diff --git a/servers/physics_2d/collision_object_2d_sw.h b/servers/physics_2d/collision_object_2d_sw.h
index c3b9e4b713..f2b2363499 100644
--- a/servers/physics_2d/collision_object_2d_sw.h
+++ b/servers/physics_2d/collision_object_2d_sw.h
@@ -112,23 +112,23 @@ public:
 
 	_FORCE_INLINE_ int get_shape_count() const { return shapes.size(); }
 	_FORCE_INLINE_ Shape2DSW *get_shape(int p_index) const {
-		ERR_FAIL_INDEX_V(p_index, shapes.size(), NULL);
+		CRASH_BAD_INDEX(p_index, shapes.size());
 		return shapes[p_index].shape;
 	}
 	_FORCE_INLINE_ const Transform2D &get_shape_transform(int p_index) const {
-		ERR_FAIL_INDEX_V(p_index, shapes.size(), Transform2D());
+		CRASH_BAD_INDEX(p_index, shapes.size());
 		return shapes[p_index].xform;
 	}
 	_FORCE_INLINE_ const Transform2D &get_shape_inv_transform(int p_index) const {
-		ERR_FAIL_INDEX_V(p_index, shapes.size(), Transform2D());
+		CRASH_BAD_INDEX(p_index, shapes.size());
 		return shapes[p_index].xform_inv;
 	}
 	_FORCE_INLINE_ const Rect2 &get_shape_aabb(int p_index) const {
-		ERR_FAIL_INDEX_V(p_index, shapes.size(), Rect2());
+		CRASH_BAD_INDEX(p_index, shapes.size());
 		return shapes[p_index].aabb_cache;
 	}
 	_FORCE_INLINE_ const Variant &get_shape_metadata(int p_index) const {
-		ERR_FAIL_INDEX_V(p_index, shapes.size(), Variant());
+		CRASH_BAD_INDEX(p_index, shapes.size());
 		return shapes[p_index].metadata;
 	}
 
@@ -138,16 +138,16 @@ public:
 
 	void set_shape_as_disabled(int p_idx, bool p_disabled);
 	_FORCE_INLINE_ bool is_shape_set_as_disabled(int p_idx) const {
-		ERR_FAIL_INDEX_V(p_idx, shapes.size(), false);
+		CRASH_BAD_INDEX(p_idx, shapes.size());
 		return shapes[p_idx].disabled;
 	}
 
 	_FORCE_INLINE_ void set_shape_as_one_way_collision(int p_idx, bool p_one_way_collision) {
-		ERR_FAIL_INDEX(p_idx, shapes.size());
+		CRASH_BAD_INDEX(p_idx, shapes.size());
 		shapes.write[p_idx].one_way_collision = p_one_way_collision;
 	}
 	_FORCE_INLINE_ bool is_shape_set_as_one_way_collision(int p_idx) const {
-		ERR_FAIL_INDEX_V(p_idx, shapes.size(), false);
+		CRASH_BAD_INDEX(p_idx, shapes.size());
 		return shapes[p_idx].one_way_collision;
 	}