abg-symtab-reader.{h,cc} shall contain the refactored symtab reader.
Create the stub files, an empty unit test and hook everything up in the
make system.
* src/abg-symtab-reader.h: New header file.
* src/abg-symtab-reader.cc: New source file.
* src/Makefile.am: Add new source files.
* tests/Makefile.am: Add new test case runtestsymtabreader.
* tests/test-symtab-reader.cc: New test source file.
Reviewed-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Matthias Maennich <maennich@google.com>