Dagger: decompilation to LLVM IR

Dagger is a decompilation framework based on LLVM. It enables existing backends to easily provide instruction-level semantics. These are then used to translate target instructions to an IR-like architecture, Mir (for micro-IR), and further to LLVM IR itself. Dagger also enables easy retargetability of several planned tools, like rewriters, static or dynamic binary translators (with valgrind-like instrumentation), and even simple instruction set emulators. The IR can also be transformed to do static analysis, or even, using a revived and improved C backend, full-blown decompilation.