Tag source files with license comment

Updates the source files with a header comment that includes the copyright and reference to the `LICENSE` file. I added a test that will be run with smoke tests to verify the copyright exists in all source files. This will alert us when new files are added and do not include the comment.

The test checks the year, so we can expect it to fail on the first of each new year. I have not included any scripts to automate the process of updating the copyright each year. I think we can do that later... but, I'm open to other suggestions.

To add the comments to all these files, I ran the following two find commands. Those commands were taken from `make -f make/Makefile.release`, which was formerly run when creating the release tarball.

```bash
find compiler runtime make modules \
    -name Make\* -o \
    -name \*.c -o \
    -name \*.chpl -o \
    -name \*.cpp -o \
    -name \*.g -o \
    -name \*.h -o \
    -name \*.lex -o \
    -name \*.y -o \
    -name \*.ypp | \
    grep -v compiler/parser/chapel.tab.h | \
    grep -v compiler/parser/chapel.tab.cpp | \
    xargs ./util/buildRelease/add_license_to_sources.py

find . -maxdepth 1 \
    -name Make\* | \
    xargs ./util/buildRelease/add_license_to_sources.py
```

Reviewer should pay attention to these file changes:

* `util/buildRelease/add_license_to_sources.py` - adds copyright/license comment to one or more source file(s)
* `util/buildRelease/license_text_for_comment.txt` - raw text used by above
* `util/test/checkCopyright.bash` - verifies all sources have copyright
* `util/buildRelease/smokeTest` - calls `checkCopyright.bash` so we will know when someone checks in a new file without one of these comments
* `make/Makefile.release` - removed as it is no longer needed
* `util/buildRelease/gen_release` - does not call `make/Makefile.release`

### TODO
* [x] test pass, since 615 files did change...