Small simplification of #include dependencies.

Small simplification of #include dependencies.

Remove messages.h from v8.h and include it explicitly in only the few places
it is needed.  Many files relied on getting handles-inl.h implicitly from
messages.h through v8.h, so include handles-inl.h explicitly in v8.h
instead.

Remove zone-inl.h from header files where it is not needed, can be replaced
by a forward declaration, or can be replaced by zone.h (specifically,
factory.h and heap.h).  Include zone.h or zone-inl.h in header files where
it was implicitly included via heap.h or factory.h.  Prefer zone.h over
zone-inl.h in header files where possible by including zone-inl.h in .cc
files.

Committed: http://code.google.com/p/v8/source/detail?r=4058

[Kevin Millikin (Chromium), 2010-03-08 05:03:24]

I had to add -fno-strict-aliasing in order to compile with gcc 4.4.1.  I can
commit without that change if we wish.

[Mads Ager (chromium), 2010-03-08 07:52:03]

LGTM