Introduce ObjectLoader and RSExecutable.

ObjectLoader loads an object file into memory.

ObjectLoaderImpl defines a set of format-independent interfaces
that a object file format loader has to provide.

ELFObjectLoaderImpl is a subclass of ObjectLoaderImpl and can be used
to load an ELF relocatable object built based on librsloader. It
directly uses the C++ APIs provided by librsloader instead of using
wrapped C APIs defined in librsloader.h

RSExecutable holds the build results of a RSScript.

Change-Id: Ib73d3f567fce3dcfea8c9f2c9bc19fbc47ec78bc
8 files changed