Add language option in -gdb-show command (MI)

Summary:
Add language option in -gdb-show command + test:
```
$ bin/lldb-mi ~/p/hello
[...]
b main
[...]
r
[...]
(gdb)
-gdb-show language
^done,value="c++"
(gdb)
quit
```

Test Plan: ./dotest.py -v --executable $BUILDDIR/bin/lldb tools/lldb-mi/

Reviewers: abidh, granata.enrico, jingham, clayborg

Reviewed By: clayborg

Subscribers: lldb-commits, jingham, granata.enrico, clayborg, abidh

Differential Revision: http://reviews.llvm.org/D9279

llvm-svn: 235983
diff --git a/lldb/source/API/SBLanguageRuntime.cpp b/lldb/source/API/SBLanguageRuntime.cpp
new file mode 100644
index 0000000..93a54cd
--- /dev/null
+++ b/lldb/source/API/SBLanguageRuntime.cpp
@@ -0,0 +1,26 @@
+//===-- SBLanguageRuntime.cpp -----------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/API/SBLanguageRuntime.h"
+#include "lldb/Target/LanguageRuntime.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+lldb::LanguageType
+SBLanguageRuntime::GetLanguageTypeFromString (const char *string)
+{
+    return LanguageRuntime::GetLanguageTypeFromString(string);
+}
+
+const char *
+SBLanguageRuntime::GetNameForLanguageType (lldb::LanguageType language)
+{
+    return LanguageRuntime::GetNameForLanguageType(language);
+}