[release] v1.2.0

Update 1.2 introduces a host of new features, mostly for the VM, to support modding frameworks like Ikarus and LeGo.
There are also many bugfixes, which mostly address issues with games files provided by mods. Notably, there is one
small breaking change which only affects users who have been manually passing include_polygons to mesh::parse() ,
as described below.

Breaking Changes

• [33f6f6d] For performance reasons, mesh::parse() now takes a vector of ints instead of an unordered_set. Thanks, @Try!

Features

• [69f1df0] You can now call script functions manually, pushing values onto the stack as required, by using
  vm::unsafe_call(). This addition was made for compatibility with the C interface.
• [637b888] You can now register a custom default external function for manually handling the stack. This addition was
  made for compatibility with the C interface.
• [78a1c82] Added a new implementation of the VFS in the form of Vfs. This will fully replace the old vdf_file
  implementation in phoenix 2.0.
• [5230465] Meshes can now be parsed without passing include_polygons.
• [bbec4cc,f46144fa] Added named constants for Gothic 1/2 specific enum values in npc_type.
• [e481bca] The VM now supports overriding functions in a way which will not push a call stack frame ("naked functions"). Thanks, @Try!
• [e481bca] The VM can now report accesses of specific symbols by calling a registered callback. This is required for
  supporting the Ikarus modding framework as well as debugging support. Thanks, @Try!
• [13c929b] Daedalus function parameters for externals can now be explicitly passed using a new func type,
  instead of a plain int.
• [a348a38] The VM now supports two new instance types, opaque_instance and transient_instance, which can be used
  to support modding frameworks like Ikarus. Thanks, @Try!

Bugfixes

• [2c2a099] vm::call_function() now properly compiles when building a shared library.
• [b4af7ed] The camera_trajectory enum now contains the correct enum value for camera_trajectory::object.
• [fee2dd1] Added support for semicolons in model script source files.
• [ed37464] The buffer now no longer segfaults when loading empty files.
• [68714df] When reading a line at EOF, the buffer no longer throws an exception, but rather returns the empty string.
• [356647d] light_preset and light VObs now correctly support greyscale color transitions.
• [3fe0f7b] Parsing of model scripts now features improved compatibility for modded installations.
• [0e7e507] For compatibility with mods, values of Daedalus string symbols are now parsed using a special algorithm
  to avoid data corruption.
• [9e8458e,7e447c3e,bcb47c1b] The Vfs now correctly handles trailing whitespace in node names.

Misc

• [4ac598e] textures can now be copied and moved.
• [1d6a3b7] scripts can now be copied and moved.
• [19ab9ac] Buffer exception constructors are now public.
• [d6566d5,bee00d13] VM stack traces are now printed using the logger.
• [3b6825b] The element count of c_item::{text, count} has been extracted as a constant. Thanks, @JucanAndreiDaniel!

Deprecations

• [78a1c82] Deprecated the old VFS implementation in vdfs.hh.