a WebP encoder

converts PNG & JPEG to WebP

This is an experimental early version, with lot of room
of later optimizations in both speed and quality.

Compile with the usual `./configure && make`
Command line example is examples/cwebp

Usage:

   cwebp [options] -q quality input.png -o output.webp

where 'quality' is between 0 (poor) to 100 (very good).
Typical value is around 80.

More encoding options with 'cwebp -longhelp'

Change-Id: I577a94f6f622a0c44bdfa9daf1086ace89d45539

src/Makefile.am

@@ -0,0 +1,12 @@
+SUBDIRS = dec enc
+
+AM_CPPFLAGS = -I$(top_builddir)/src
+lib_LTLIBRARIES = libwebp.la
+
+libwebp_la_SOURCES =
+libwebp_la_LIBADD = dec/libwebpdecode.la \
+                    enc/libwebpencode.la
+libwebp_la_LDFLAGS = -version-info 0:0:0
+libwebpinclude_HEADERS = webp/types.h webp/decode.h webp/decode_vp8.h \
+                         webp/encode.h
+libwebpincludedir = $(includedir)/webp