Fix clang style warnings in webrtc/modules/audio_coding/neteq

Mostly this consists of marking functions with override when
applicable, and moving function bodies from .h to .cc files.

BUG=163
R=henrik.lundin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/44109004

Cr-Commit-Position: refs/heads/master@{#8960}
diff --git a/webrtc/modules/audio_coding/neteq/neteq_impl.cc b/webrtc/modules/audio_coding/neteq/neteq_impl.cc
index 32c6629..784174f 100644
--- a/webrtc/modules/audio_coding/neteq/neteq_impl.cc
+++ b/webrtc/modules/audio_coding/neteq/neteq_impl.cc
@@ -281,6 +281,18 @@
   return delay_manager_->least_required_delay_ms();
 }
 
+int NetEqImpl::SetTargetDelay() {
+  return kNotImplemented;
+}
+
+int NetEqImpl::TargetDelay() {
+  return kNotImplemented;
+}
+
+int NetEqImpl::CurrentDelay() {
+  return kNotImplemented;
+}
+
 // Deprecated.
 // TODO(henrik.lundin) Delete.
 void NetEqImpl::SetPlayoutMode(NetEqPlayoutMode mode) {
@@ -354,6 +366,14 @@
   return true;
 }
 
+int NetEqImpl::SetTargetNumberOfChannels() {
+  return kNotImplemented;
+}
+
+int NetEqImpl::SetTargetSampleRate() {
+  return kNotImplemented;
+}
+
 int NetEqImpl::LastError() const {
   CriticalSectionScoped lock(crit_sect_.get());
   return error_code_;