Improve the library documentation.

Add many comments to the core math library.  Fix mulitple errors encountered when running doxygen.

Change-Id: Icbc9d8f5b5353c40b1ed6b04baef3d5c6b5888f1
diff --git a/api/gen_runtime.cpp b/api/gen_runtime.cpp
index 4570d68..fc60c9e 100644
--- a/api/gen_runtime.cpp
+++ b/api/gen_runtime.cpp
@@ -77,6 +77,10 @@
             " * See the License for the specific language governing permissions and\n"
             " * limitations under the License.\n"
             " */\n\n";
+const char* DOX_HEADER =
+            "/** @file\n"
+            " *\n"
+            " */\n\n";
 
 class Function;
 class Specification;
@@ -745,6 +749,8 @@
     }
     headerFile << LEGAL_NOTICE;
     headerFile << AUTO_GENERATED_WARNING;
+    headerFile << DOX_HEADER;
+
     writeIfdef(headerFile, headerFileName, true);
 
     // Write the functions to the header and test files.
@@ -1188,7 +1194,7 @@
         }
     }
 
-    file << "/*\n";
+    file << "/**\n";
     for (size_t ct = 0; ct < mComment.size(); ct++) {
         if (!mComment[ct].empty()) {
             file << " * " << mComment[ct] << "\n";