Convert to C++ Bison output

We have to step up to a GLR parser to do this without exceptions (for no
reason other than Bison happens to use exceptions for the LALR(1) template and
not for the GLR one), but this should let us smooth out integration going
forward.

Change-Id: Iff44662914b4a65dfa5612d07c3a1ede07e6e4a9
Signed-off-by: Casey Dahlin <sadmac@google.com>