Clarify that libnice 0.1.18 is recommended

Author: lminiero

README.md

@@ -17,7 +17,7 @@ To install it, you'll need to satisfy the following dependencies:
 
 * [Jansson](http://www.digip.org/jansson/)
 * [libconfig](https://hyperrealm.github.io/libconfig/)
-* [libnice](https://libnice.freedesktop.org/) (at least v0.1.16 suggested, master recommended)
+* [libnice](https://libnice.freedesktop.org/) (at least v0.1.16 suggested, v0.1.18 recommended)
 * [OpenSSL](http://www.openssl.org/) (at least v1.0.1e)
 * [libsrtp](https://github.com/cisco/libsrtp) (at least v2.x suggested)
 * [usrsctp](https://github.com/sctplab/usrsctp) (only needed if you are interested in Data Channels)

mainpage.dox

@@ -89,7 +89,7 @@
  * - \b gengetopt: http://www.gnu.org/software/gengetopt/ (command line)
  * - \b Jansson: http://www.digip.org/jansson/ (JSON)
  * - \b libconfig: https://hyperrealm.github.io/libconfig/ (configuration files)
- * - \b libnice: https://libnice.freedesktop.org/ (ICE/STUN/TURN, at least v0.1.16 suggested, master recommended)
+ * - \b libnice: https://libnice.freedesktop.org/ (ICE/STUN/TURN, at least v0.1.16 suggested, v0.1.18 recommended)
  * - \b OpenSSL: http://www.openssl.org/ (DTLS, at least v1.0.1e)
  * - \b libsrtp: https://github.com/cisco/libsrtp (SRTP, at least v2.x suggested)
  * - \b usrsctp: http://code.google.com/p/sctp-refimpl/ (\c optional, Data Channels)
@@ -3745,7 +3745,7 @@ ldd janus | grep asan
  * - \b gengetopt: http://www.gnu.org/software/gengetopt/ (command line)
  * - \b Jansson: http://www.digip.org/jansson/ (JSON)
  * - \b libconfig: https://hyperrealm.github.io/libconfig/ (configuration files)
- * - \b libnice: https://libnice.freedesktop.org/ (ICE/STUN/TURN, at least v0.1.16 suggested, master recommended)
+ * - \b libnice: https://libnice.freedesktop.org/ (ICE/STUN/TURN, at least v0.1.16 suggested, v0.1.18 recommended)
  * - \b OpenSSL: http://www.openssl.org/ (DTLS, at least v1.0.1e)
  * - \b libsrtp: https://github.com/cisco/libsrtp (SRTP, at least v2.x suggested)
  * - \b usrsctp: http://code.google.com/p/sctp-refimpl/ (\c optional, Data Channels)