* Separate OS and Target conceptually; now an OS is created on an
existing target which must have ROM bound.
* Add a configuration file with a data library and description files
which are automatically loaded at startup.
* As a first application, implement target descriptions. It is now
possible (given the proper library) to type [fxos info fx@3.10] to get
information on the fx OS version 3.10.
* Set up the pass infrastructure and the first few easy passes. This
is still a Work In Progress and not yet called from the command-line.
* Improve the copy/move behavior of classes (C++ concerns).
* Add instruction metadata, which will make it easier to write actual
useful analysis passes.
* switch from File to Buffer to manage file contents
* boilerplate for a proprer command-line interface, and complete help
* add a notion of Addressable to avoid losing the source address of very
information provided by the OS type
* use addressables in the AbstractMemory interface
* fully parse the header and footer of OSes
* bring [fxos info] to the level of the previous implementation
* make most of the OS attributes public
* use char* instead of void* for translation, since void* arithmetic
triggers a hell of warnings in C++