[gtk+] docs: Update references to Meson CLI utilities

[Emmanuele Bassi <ebassi src gnome org>]

commit 9957dd59b04bafb13b3e4ef5dfd0a344972f70b7
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Aug 15 14:08:57 2017 +0100

    docs: Update references to Meson CLI utilities
    
    The separate `mesonconf` and `mesontest` binaries have been deprecated,
    in favour of `meson` sub-commands.

 README.md                        |    2 +-
 docs/RELEASE-HOWTO.md            |    2 +-
 docs/reference/gtk/building.sgml |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/README.md b/README.md
index e4ad8ea..0245538 100644
--- a/README.md
+++ b/README.md
@@ -84,7 +84,7 @@ $ ninja
 You can run the test suite using:
 
 ```sh
-$ mesontest
+$ meson test
 ```
 
 And, finally, you can install GTK+ using:
diff --git a/docs/RELEASE-HOWTO.md b/docs/RELEASE-HOWTO.md
index c47d95f..716eac6 100644
--- a/docs/RELEASE-HOWTO.md
+++ b/docs/RELEASE-HOWTO.md
@@ -54,7 +54,7 @@ $ ninja -C _build gtk40-properties-pot
      release. **Note**: this is critical, a slip-up here will cause the soname
      to change.
 
-  6. Make sure that `mesontest` is happy (`ninja dist` will also run the test
+  6. Make sure that `meson test` is happy (`ninja dist` will also run the test
      suite, but it's better to catch issues before committing and tagging
      the release). Typical problems to expect here (depending on whether this
      is a devel  snapshot or a stable release):
diff --git a/docs/reference/gtk/building.sgml b/docs/reference/gtk/building.sgml
index fd5f076..2f2dc1b 100644
--- a/docs/reference/gtk/building.sgml
+++ b/docs/reference/gtk/building.sgml
@@ -56,7 +56,7 @@ How to compile GTK+ itself
     </para>
     <para>
       You can get a list of all available options for the build by
-      running <application>mesonconf</application>.
+      running <application>meson configure</application>.
     </para>
     <para>
       After Meson successfully configured the build directory, you then