Compilation fixes on GCC 4.8.1 Linux (updated with latest tests changes)

Wno-unused-function is for unused static functions begin_flat_unsafe and end_flat_unsafe. I can be reactivated if those are removed.
Wno-overloaded-virtual is for boost program options https://svn.boost.org/trac/boost/ticket/7660 

asl_dev target is because adobe_platform_libraries requires it. 
With that change, the APL build starts (but fails to compile anything serious under Linux, obviously).