Add support for packed clients (#802)

* First iteration of pack reader and interface

* Fix memory leak and remove logs

* Complete packed asset interface and begin on file loading replacement

* Implement proper BinaryIO error

* Improve AssetMemoryBuffer for reading and implement more reading

* Repair more file loading code and improve how navmeshes are loaded

* Missing checks implementation

* Revert addition of Manifest class and migration changes

* Resolved all feedback.

dCommon/GeneralUtils.cpp

@@ -50,6 +50,7 @@ bool _IsSuffixChar(uint8_t c) {
 
 bool GeneralUtils::_NextUTF8Char(std::string_view& slice, uint32_t& out) {
 	size_t rem = slice.length();
+	if (slice.empty()) return false;
 	const uint8_t* bytes = (const uint8_t*)&slice.front();
 	if (rem > 0) {
 		uint8_t first = bytes[0];