this is the first step in unifying surfacetexture and surface.
for this reason the header files were not moved, as most of them
will eventually go away.
NOTE: currently we keep libsurfaceflinger_client.so as an empty
library to workaround prebuilt binaries wrongly linking against
it.
Change-Id: I130f0de2428e8579033dc41394d093f4e1431a00
executables have calls to some shared libraries without explicitly linking
them. Currently it works as linker links these libraries via dependencies of
other libraries. This is fragile and not the right thing to do.