Release 0.3.0. Update CHANGELOG & bump version
Change license from AGPLv3 to AGPLv3-or-later
Prefix debug files (like out.ll) with ".dbg." to make invisible

Also gitignore them
Copy LICENSE to MOD_DIR when installing
Fix copying std modules from incorrect dir carth-std/
Update README to reflect new build procedure with `make install`
Un-hardcode lib and mod dir paths. Configurable at compiletime now

Compile lib and mod dirs into binary using TemplateHaskell & add
Makefile with installation targets. `make install` now compiles the
whole project and installs the `carth` binary, the
`libcarth_foreign_core.a` static lib, and the `std/std.carth` standard
library to a configurable path (default ~/.carth/bin, ~/.carth/lib,
and ~/.carth/mod respectively).
Disclaim WIP status in readme
Fix subst not applied to accesses of varbindings of DLeaf
Fix not checking in dec tree Access if type vars bound
Remove remnants of AnnotAst.Fun
Allow patterns in parameter of fun

Refutable patterns will raise an error in the type checker.

Added bonus is that `fun` is now equivalent to a sugared, special case
of `fun-match`, and is desugared as such in Infer.
unsugar -> desugar
Allow Box in pattern to dereference
Fix some minor warnings
Fix some trivial warnings
Update std with undefined & panic functionality
Handle unit and other zero-sized types in alignmentof & sizeof
Delay StartNotDefined error until after typechecking
Make Pair a builtin datatype