callview: improve ui for current and incoming callview

Modify buttons style in incoming and current callview.

Change-Id: I7ee2245596e5587c4aa6072b9117c433241d63a2
diff --git a/pixmaps/ic_mic_white_24px.svg b/pixmaps/ic_mic_white_24px.svg
new file mode 100644
index 0000000..d3eb25e
--- /dev/null
+++ b/pixmaps/ic_mic_white_24px.svg
@@ -0,0 +1,4 @@
+<svg fill="#ffffff" height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg">
+    <path d="M12 14c1.66 0 2.99-1.34 2.99-3L15 5c0-1.66-1.34-3-3-3S9 3.34 9 5v6c0 1.66 1.34 3 3 3zm5.3-3c0 3-2.54 5.1-5.3 5.1S6.7 14 6.7 11H5c0 3.41 2.72 6.23 6 6.72V21h2v-3.28c3.28-.48 6-3.3 6-6.72h-1.7z"/>
+    <path d="M0 0h24v24H0z" fill="none"/>
+</svg>