Sync src with amalgamated versions

Now src contains exactly what's embedded in mongoose.c and .h, nothing more.

Added `tools/amalgam.sh` to aamlgamate both files at once.

There are no functional changes to mongoose.c, .h in this PR, only slight filename changes.

src/common/platforms/windows/windows_direct.c

@@ -1,19 +1,3 @@
-/*
- * Copyright (c) 2014-2018 Cesanta Software Limited
- * All rights reserved
- *
- * Licensed under the Apache License, Version 2.0 (the ""License"");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an ""AS IS"" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
 
 #ifdef _WIN32