Moved vendored js/css into public/vendor and documented sources (#1484) (#2241)

* Cleaning up public/ and documenting js/css libs.

This commit mostly addresses #1484 by moving vendor'ed plugins into a
vendor/ directory and documenting their upstream source and license in
vendor/librejs.html.

This also proves gitea is using only open source js/css libraries which
helps toward reaching #1524.

* Removing unused css file.

The version of this file in use is located at:
  vendor/plugins/highlight/github.css

* Cleaned up librejs.html and added javascript header

A SafeJS function was added to templates/helper.go to allow keeping
comments inside of javascript.

A javascript comment was added in the header of templates/base/head.tmpl
to mark all non-inline source as free.

The librejs.html file was updated to meet the current librejs spec. I
have now verified that the librejs plugin detects most of the scripts
included in gitea and suspect the non-free detections are the result of
a bug in the plugin. I believe this commit is enough to meet the C0.0
requirement of #1534.

* Updating SafeJS function per lint suggestion

* Added VERSIONS file, per request

public/vendor/plugins/codemirror/mode/cmake/cmake.js

@@ -0,0 +1,97 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+(function(mod) {
+  if (typeof exports == "object" && typeof module == "object")
+    mod(require("../../lib/codemirror"));
+  else if (typeof define == "function" && define.amd)
+    define(["../../lib/codemirror"], mod);
+  else
+    mod(CodeMirror);
+})(function(CodeMirror) {
+"use strict";
+
+CodeMirror.defineMode("cmake", function () {
+  var variable_regex = /({)?[a-zA-Z0-9_]+(})?/;
+
+  function tokenString(stream, state) {
+    var current, prev, found_var = false;
+    while (!stream.eol() && (current = stream.next()) != state.pending) {
+      if (current === '$' && prev != '\\' && state.pending == '"') {
+        found_var = true;
+        break;
+      }
+      prev = current;
+    }
+    if (found_var) {
+      stream.backUp(1);
+    }
+    if (current == state.pending) {
+      state.continueString = false;
+    } else {
+      state.continueString = true;
+    }
+    return "string";
+  }
+
+  function tokenize(stream, state) {
+    var ch = stream.next();
+
+    // Have we found a variable?
+    if (ch === '$') {
+      if (stream.match(variable_regex)) {
+        return 'variable-2';
+      }
+      return 'variable';
+    }
+    // Should we still be looking for the end of a string?
+    if (state.continueString) {
+      // If so, go through the loop again
+      stream.backUp(1);
+      return tokenString(stream, state);
+    }
+    // Do we just have a function on our hands?
+    // In 'cmake_minimum_required (VERSION 2.8.8)', 'cmake_minimum_required' is matched
+    if (stream.match(/(\s+)?\w+\(/) || stream.match(/(\s+)?\w+\ \(/)) {
+      stream.backUp(1);
+      return 'def';
+    }
+    if (ch == "#") {
+      stream.skipToEnd();
+      return "comment";
+    }
+    // Have we found a string?
+    if (ch == "'" || ch == '"') {
+      // Store the type (single or double)
+      state.pending = ch;
+      // Perform the looping function to find the end
+      return tokenString(stream, state);
+    }
+    if (ch == '(' || ch == ')') {
+      return 'bracket';
+    }
+    if (ch.match(/[0-9]/)) {
+      return 'number';
+    }
+    stream.eatWhile(/[\w-]/);
+    return null;
+  }
+  return {
+    startState: function () {
+      var state = {};
+      state.inDefinition = false;
+      state.inInclude = false;
+      state.continueString = false;
+      state.pending = false;
+      return state;
+    },
+    token: function (stream, state) {
+      if (stream.eatSpace()) return null;
+      return tokenize(stream, state);
+    }
+  };
+});
+
+CodeMirror.defineMIME("text/x-cmake", "cmake");
+
+});