Support for LastFM scrobbling (issue #19)

INSTALL

@@ -29,6 +29,8 @@ sudo apt-get install \
 Depending on the version of libav/ffmpeg in your distribution you may also need
 libavresample-dev.
 
+To build with LastFM support, you should also install libcurl4-openssl-dev.
+
 Note that while forked-daapd will work with versions of libevent between 2.0.0
 and 2.1.3, it is recommended to use either libevent 1 or 2.1.4+. Otherwise you
 will not have support for Shoutcast metadata and simultaneous streaming to
@@ -108,6 +110,8 @@ Libraries:
         from <http://github.com/JonathanBeck/libplist/downloads>
  - libspotify (optional - Spotify support)
         from <https://developer.spotify.com>
+ - libcurl (optional - LastFM support)
+        from <http://curl.haxx.se/libcurl/>
 
 If using binary packages, remember that you need the development packages to
 build forked-daapd (usually named -dev or -devel).
@@ -161,6 +165,9 @@ though you compiled with --enable-spotify, the executable will still be able
 to run on systems without libspotify (the Spotify features will then be 
 disabled).
 
+Support for LastFM scrobbling is optional. Use --enable-lastfm to enable this
+feature.
+
 Support for iTunes Music Library XML format is optional. Use --enable-itunes
 to enable this feature.