Use eSpeak NG consistently to refer to the new project.

README.md

 
 ### eSpeak NG Feature Configuration
 
-The following `configure` options control which eSpeak features are enabled:
+The following `configure` options control which eSpeak NG features are enabled:
 
 | Option          | Description                                  | Default |
 |-----------------|----------------------------------------------|---------|

configure.ac

 AC_PREREQ([2.63])
-AC_INIT([eSpeak], [1.48], [https://github.com/rhdunn/espeak/issues], [espeak], [https://github.com/rhdunn/espeak])
+AC_INIT([eSpeak NG], [1.48], [https://github.com/rhdunn/espeak/issues], [espeak], [https://github.com/rhdunn/espeak])
 AM_INIT_AUTOMAKE()
 
 m4_ifdef([AM_SILENT_RULES],[AM_SILENT_RULES])
 
 AC_MSG_NOTICE([
 
-    Configuration for eSpeak complete.
+    Configuration for eSpeak NG complete.
 
         Source code location:          ${srcdir}