Update the README to mention that a C API is also available.

README

Index: README
diff --git a/README b/README
index 6fec766f0139676fe99c8cb8e6973bcf3fb7b3d2..42193796ee428ef4a867a0549f7f4af43b868f0d 100644
--- a/README
+++ b/README
@@ -11,10 +11,10 @@ transport to the UMA server.
 The Metrics Library: libmetrics
 ================================================================================
 
-libmetrics is a small library that implements the basic C++ API for
-metrics collection. All metrics collection is funneled through this
-library. The easiest and recommended way for a client-side module to
-collect user metrics is to link libmetrics and use its APIs to send
+libmetrics is a small library that implements the basic C and C++ API
+for metrics collection. All metrics collection is funneled through
+this library. The easiest and recommended way for a client-side module
+to collect user metrics is to link libmetrics and use its APIs to send
 metrics to Chrome for transport to UMA. In order to use the library in
 a module, you need to do the following:
 
@@ -47,6 +47,8 @@ a module, you need to do the following:
   complete API documentation in metrics_library.h under
   src/platform/metrics/.
 
+  For more information on the C API see c_metrics_library.h.
+
 - On the target platform, shortly after the sample is sent it should
   be visible in Chrome through "about:histograms".
 
@@ -59,7 +61,6 @@ Use TrackerArea.MetricName. For example:
 
 Logging.CrashCounter
 Network.TimeToDrop
-Platform.BootTime
 
 
 ================================================================================