Reduce unnecessary COW on Vector by make writing explicit

This commit makes operator[] on Vector const and adds a write proxy to it.  From
now on writes to Vectors need to happen through the .write proxy. So for
instance:

Vector<int> vec;
vec.push_back(10);
std::cout << vec[0] << std::endl;
vec.write[0] = 20;

Failing to use the .write proxy will cause a compilation error.

In addition COWable datatypes can now embed a CowData pointer to their data.
This means that String, CharString, and VMap no longer use or derive from
Vector.

_ALWAYS_INLINE_ and _FORCE_INLINE_ are now equivalent for debug and non-debug
builds. This is a lot faster for Vector in the editor and while running tests.
The reason why this difference used to exist is because force-inlined methods
used to give a bad debugging experience. After extensive testing with modern
compilers this is no longer the case.

1 files changed, 3 insertions, 3 deletions

diff --git a/modules/gdscript/gdscript.h b/modules/gdscript/gdscript.h
index d5fe7a000b..79ac9ed413 100644
--- a/modules/gdscript/gdscript.h
+++ b/modules/gdscript/gdscript.h
@@ -355,10 +355,10 @@ public:
 		Vector<StackInfo> csi;
 		csi.resize(_debug_call_stack_pos);
 		for (int i = 0; i < _debug_call_stack_pos; i++) {
-			csi[_debug_call_stack_pos - i - 1].line = _call_stack[i].line ? *_call_stack[i].line : 0;
+			csi.write[_debug_call_stack_pos - i - 1].line = _call_stack[i].line ? *_call_stack[i].line : 0;
 			if (_call_stack[i].function)
-				csi[_debug_call_stack_pos - i - 1].func = _call_stack[i].function->get_name();
-			csi[_debug_call_stack_pos - i - 1].file = _call_stack[i].function->get_script()->get_path();
+				csi.write[_debug_call_stack_pos - i - 1].func = _call_stack[i].function->get_name();
+			csi.write[_debug_call_stack_pos - i - 1].file = _call_stack[i].function->get_script()->get_path();
 		}
 		return csi;
 	}