Add .gitignore everywhere based on .cvsignore.

* .gitignore: New.
* build-aux/.gitignore: New.
* data/.gitignore: New.
* doc/.gitignore: New.
* etc/.gitignore: New.
* examples/.gitignore: New.
* examples/calc++/.gitignore: New.
* lib/.gitignore: New.
* m4/.gitignore: New.
* po/.gitignore: New.
* runtime-po/.gitignore: New.
* src/.gitignore: New.
* tests/.gitignore: New.

src/.gitignore

@@ -0,0 +1,13 @@
+/*.flc
+/*.log
+/*.o
+/*.output
+/.deps
+/Makefile
+/Makefile.in
+/bison
+/revision.c
+/scan-code.c
+/scan-gram.c
+/scan-skel.c
+/yacc