improves symbolization facilities

[ivg]

Implements support for various relocations and improves existing that
enables us to pass all tests without relying on external symbols or
tools such as objdump or radare2.

This branch support PLT-like relocations, as well as direct calls with
GLOB_DAT relocations (fixes #1135). The PLT entries are constant
folded and memory references are then analyzed. We also extended the
analysis that detects stub functions to support various ABI and file
formats. For PowerPC MachO, that stores stubs directly in the text
section, we implemented a signature matching procedure to reliably
detect the stubs. We also significantly improved support of mips,
which was sufferening from missing function starts that correspond to
the stubbed functions as byteweigh is unable to detect these stubs.

In addition, this PR brings a new library called Bap_relation that is
a bidirectional mapping useful for storing addr <-> name mapping and
ensure their bijection. This library is now used explicitly or
implicitly (via the old symbolizer interface) by all our providers of
symbolic information. This change prevents symbolizers from providing
conflicting information, which may later lead to the knowledge base
conflicts.

We also removed so far the name to address translation service that we
recently introduced #1119. We are not ready for this service yet (our
knowledge base is not having enough rules stored in it) and without
this rule we can disassemble 25% faster.

There are also a couple of minor fixes and quality of life
improvements:

• fixes Insn.dests domain functions
• a better default for the KB.Domain.Powerset inspect parameter
• makes glibc-runtime heuristic more aggressive

[ivg]

@gitoleg, can you please prepare a sattelite PR to our opam-repository that will reflect the oasis folder changes as well as add the new library.