added .gitignore

- .gitignore containing patterns for all the files that git should
   ignore (from *.o, *.d to config.mak, modules.lst  a.s.o).

.gitignore

@@ -0,0 +1,28 @@
+# ignore autogenerated files
+cfg.tab.c
+cfg.tab.h
+lex.yy.c
+librpath.lst
+makecfg.lst
+config.mak
+modules.lst
+# ignore dependency files
+*.d
+# ignore binary files and objects
+ser
+*.so
+*.so.*
+*.o
+# archives
+*.tar.gz
+*.deb
+*.rpm
+# tags
+tags
+TAGS
+# vi swaps
+.*.swp
+# various other binaries
+test/udp_flood
+utils/gen_ha1/gen_ha1
+utils/sercmd/sercmd