add license headers to all the source files in hardware

pre-append the following header to the file as a comment to all source files:

```
Copyright © 2017, ACM@UIUC

This file is part of the Merch Project.

The Merch Project is open source software, released under the University of Illinois/NCSA Open Source License.
You should have received a copy of this license in a file with the distribution.
```

No specific files or tests are named. Start by inventorying the source files in the hardware project and checking their languages and comment syntax, then prepend the supplied header to each one. Done means every source file has the header and the project remains valid.

Escrita pelo modelo de indexação a partir do texto da issue.