add a .gitignore file

.gitignore

@@ -1,41 +1,6 @@
-*.l[ao]
-*.[ao]
-*.pc
-.deps
-.libs
-/aclocal.m4
-/ar-lib
-/autom4te.cache
-/compile
-/config.*
-/configure
-/depcomp
-/dist
-/install-sh
-/libtool
-/ltmain.sh
-/missing
-/mkinstalldirs
-/stamp-h1
-Makefile
-Makefile.in
-examples/anim_diff
-examples/[cdv]webp
-examples/gif2webp
-examples/img2webp
-examples/webpmux
-src/webp/config.h*
-src/webp/stamp-h1
-/output
-/doc/output
-*.idb
-*.pdb
-/iosbuild
-/WebP.framework
+*~
+examples/[sv]jpeg
 CMakeCache.txt
 CMakeFiles/
 cmake_install.cmake
-.gradle
 /build
-extras/get_disto
-extras/webp_quality