Bump dependency versions

.travis.yml

@@ -15,7 +15,7 @@ env:
     PKG_CONFIG_PATH="$DEPENDENCY_DIR/lib/pkgconfig:$PKG_CONFIG_PATH" \
     CFLAGS=-Werror \
     SODIUM_VERSION=1.0.16 \
-    TOXCORE_VERSION=0.2.1
+    TOXCORE_VERSION=0.2.8
 
 install:
   # install libsodium, required by libtoxcore

README.md

@@ -16,7 +16,7 @@ Standard][3].
  - File transfer
 
 ## Installation
-Tox-WeeChat is tested with [WeeChat][2] 2.1 and [TokTok c-toxcore][5] 0.2.1.
+Tox-WeeChat is tested with [WeeChat][2] 2.3 and [TokTok c-toxcore][5] 0.2.8.
 It also requires CMake 2.8.12 or newer to be built. Installation is fairly
 simple; after getting the source code, compile and install with CMake: