Add support for Pan Language

As found in repositories related to @quattor, e.g. https://github.com/quattor/template-library-core
The test file provided matches the one I submitted to Pygments.

At some point in the future when the Pygments patches land at GitHub the lexer should be updated from "Text only" to "pan".

lib/linguist/languages.yml

@@ -1500,6 +1500,13 @@ PHP:
   filenames:
   - Phakefile
 
+Pan:
+  type: programming
+  lexer: Text only
+  color: '#cc0000'
+  extensions:
+  - .pan
+
 Parrot:
   type: programming
   color: "#f3ca0a"

samples/Pan/test.pan

@@ -0,0 +1,54 @@
+object template pantest;
+
+# Very simple pan test file
+"/long/decimal" = 123;
+"/long/octal" = 0755;
+"/long/hexadecimal" = 0xFF;
+
+"/double/simple" = 0.01;
+"/double/pi" = 3.14159;
+"/double/exponent" = 1e-8;
+"/double/scientific" = 1.3E10;
+
+"/string/single" = 'Faster, but escapes like \t, \n and \x3d don''t work, but '' should work.';
+"/string/double" = "Slower, but escapes like \t, \n and \x3d do work";
+
+variable TEST = 2;
+
+"/x2" = to_string(TEST);
+"/x2" ?= 'Default value';
+
+"/x3" = 1 + 2 + value("/long/decimal");
+
+"/x4" = undef;
+
+"/x5" = null;
+
+variable e ?= error("Test error message");
+
+# include gmond config for services-monitoring
+include { 'site/ganglia/gmond/services-monitoring' };
+
+"/software/packages"=pkg_repl("httpd","2.2.3-43.sl5.3",PKG_ARCH_DEFAULT);
+"/software/packages"=pkg_repl("php");
+
+# Example function
+function show_things_view_for_stuff = {
+    thing = ARGV[0];
+    foreach( i; mything; STUFF ) {
+        if ( thing == mything ) {
+            return( true );
+        } else {
+            return SELF;
+        };
+    };
+    false;
+};
+
+variable HERE = <<EOF;
+; This example demonstrates an in-line heredoc style config file
+[main]
+awesome = true
+EOF
+
+variable small = false;#This should be highlighted normally again.