Added a Dwarf Function Finder (dff) library.

Dff library resides in a [Dff] module, so it is a good place to
start. Basic data definitions are given in [Dwarf] module. Dff library
doesn't depend on elf in general and ocaml-elf library in particular. It
uses its own abstraction, called [Dwarf_data], so a user is encouraged
to make his own translators from elf to dwarf. You can refer to
[dff_test] file as an example. Also, if first argument to [dff_test]
program is a filename, then it will print functions from this file,
e.g.:

        ./dff_test.native dff_test.native

The library was manually tested on 32-bit and 64-bit binaries, with
four compilers (gcc-4.4, gcc=4.8.2, gcc-4.9.0, clang-1.1 (sic)), but
only on GNU/Linux platform.

Also, there were minor changes, some highlights:

  - removed dependency on Quickcheck;
  - cleaned up build files;
  - updated Leb128 interface.

UPDATE: added support for indirectly specified high_pc.

Squashed commit of the following:

commit 0b2832d4c4e2e5053620aca9388a0a1b9ba721db
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:36:39 2014 +0400

    fixed leb128 test.

    Change-Id: I89a69893a9e4026335d54a4d7633c540a6432e0e

commit 0fc0d7d494691c2be658abbbd261515dd5aee680
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:34:48 2014 +0400

    yet another fix to _oasis.

    Change-Id: Ibf51e0ec439c40a84f201f44f2cf2343309ce784

commit 22d1c77c79a69637af32cc926eb40c5b92e15e40
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:33:20 2014 +0400

    fixed _oasis

    Change-Id: I93f8ced2b5a4311a7ff66a993537237b71e7e7e2

commit 8c0dc3d7e802e6a28899ca778e4d8fbe280418a5
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:30:23 2014 +0400

    removed dependency from Quickcheck

    Change-Id: I97d4b7a74151ef996c031d4e45b6fca8f773a1b3

commit 05cffb5539b128c707cfa51823c3721b25ff2027
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:14:35 2014 +0400

    updated build files.

    Change-Id: I1a9ded00ad4e6adefb578496e98b63396d8a301c

commit 2e36a132c8e0f9a5e0845f651581177a022b4a89
Merge: 2640310 81ea383
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:07:31 2014 +0400

    Merge ../dff into dwarf

commit 26403106654ed7ce12cdad07e40c34eb4078412b
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:06:43 2014 +0400

    Leb128 now conforms to a common reader interface.

    common in a core sense of view.

    Change-Id: I220b42fcae7aab365f77072f8fab26a34b434c3d

commit 81ea383f23bd6c07fc54cf9b83ca3cffd759ad70
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 19:02:29 2014 +0400

    added some command parsing to test.

commit 82ea809896b9eab262df37aaab61cf0d7226dfb9
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 18:25:19 2014 +0400

    added some documentation.

commit 1c2346112328aa13487712ab79ffc8b9bf989c0e
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 18:07:06 2014 +0400

    removed eager evaluation.

    Now all compiling units are parsed lazily.

commit 6a1675fedc6d7a6b0aa96b1a361fe6eec66bafb6
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 17:38:48 2014 +0400

    now we can parse several CUs.

commit 73cf81c1df4ba1c3aea876af817c06d563b34b58
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 16:49:24 2014 +0400

    now we can read one compilation unit.

commit 83d719d4e289fdcea43634646b5f41ad6b55a997
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 16:31:13 2014 +0400

    added graceful finishing.

commit a6b105c397c3a8bfcd259fb46465552a4dc846eb
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 16:25:44 2014 +0400

    added support form Strp form.

    Now we can read functions.

commit 2d2c8c42cae4ea78c4b8de85fad5156af09f8e8c
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 02:43:00 2014 +0400

    Carefully read spec and fixed parsers.

    1. Now parsers specifically designates the difference between elf word
    size and dwarf word_size/

    2. Removed Flag form (since it is a one byte constant), but added
       Flag_present form, that specifies empty value

    3. Added support for indirect forms.

commit 8a15a03766b85732e80efb0795ca5339e4b8b5e4
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Thu Oct 9 01:31:16 2014 +0400

    all functions are ready.

commit ce7e08b80629624ad06dfab6ca160175b48fb21d
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Wed Oct 8 21:29:48 2014 +0400

    Finished  the outline.

    Although many primitives are still stubs.

commit 7ff6a1ff6fb248b592024e72653f2b71de811905
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Tue Oct 7 22:08:51 2014 +0400

    moved temporary to my own addr type.

commit 2cf7ba50d6a9f8d49f2aa90474b199b980b22bb1
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Tue Oct 7 02:12:26 2014 +0400

    Added basic data definitions and parsers.

commit 4cd3db8b55a1dd93edf7a625cf1d6f7a46e90737
Author: Ivan Gotovchits <ivg@ieee.org>
Date:   Mon Oct 6 03:41:47 2014 +0400

    initial check-in.

Change-Id: I272b73ca7face439d2649779cfd0bb14c9df2723