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.

.gitignore

@@ -0,0 +1,29 @@
+/*.cache
+/*.flc
+/*.patch *.log log patches applied
+/*.prj
+/.version
+/ABOUT-NLS
+/COPYING
+/INSTALL
+/Makefile
+/Makefile.in
+/_*
+/a.exe
+/a.out
+/aclocal.m4
+/b.out
+/bison-*
+/conf[0-9]*
+/confdefs*
+/config.log
+/config.status
+/configure
+/configure.lineno
+/conftest*
+/gnulib
+/javacomp.sh
+/javaexec.sh
+/patches
+/releases
+/stamp-h*