[C++] Rewrite of the preprocessor.

This rewrite fixes a couple of issues with the pre-processor. It now
supports:
- macros in macro bodies
- stringification of parameters [cpp.stringize]
- the concatenation operator [cpp.concat]
- #include MACRO_HERE
- defined() inside macro bodies used in pp-conditions.

Change-Id: Ifdb78041fb6afadf44f939a4bd66ce2832b8601f
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>

tests/auto/cplusplus/preprocessor/data/noPP.1.cpp

@@ -0,0 +1,66 @@
+WRITE IN C  (sung to The Beatles "Let it Be")
+
+When I find my code in tons of trouble,
+Friends and colleagues come to me,
+Speaking words of wisdom:
+"Write in C."
+
+As the deadline fast approaches,
+And bugs are all that I can see,
+Somewhere, someone whispers"
+"Write in C."
+
+Write in C, write in C,
+Write in C, write in C.
+LISP is dead and buried,
+Write in C.
+
+I used to write a lot of FORTRAN,
+for science it worked flawlessly.
+Try using it for graphics!
+Write in C.
+
+If you've just spent nearly 30 hours
+Debugging some assembly,
+Soon you will be glad to
+Write in C.
+
+Write in C, write in C,
+Write In C, yeah, write in C.
+Only wimps use BASIC.
+Write in C.
+
+Write in C, write in C,
+Write in C, oh, write in C.
+Pascal won't quite cut it.
+Write in C.
+
+{
+  Guitar Solo
+}
+
+Write in C, write in C,
+Write in C, yeah, write in C.
+Don't even mention COBOL.
+Write in C.
+
+And when the screen is fuzzy,
+And the edior is bugging me.
+I'm sick of ones and zeroes.
+Write in C.
+
+A thousand people people swear that T.P.
+Seven is the one for me.
+I hate the word PROCEDURE,
+Write in C.
+
+Write in C, write in C,
+Write in C, yeah, write in C.
+PL1 is 80's,
+Write in C.
+
+Write in C, write in C,
+Write in C, yeah, write in C.
+The government loves ADA,
+Write in C.
+