Add -E support in executables, for use by launchers in forwarding the
environment to the user program processes when the underlying system
launcher can't do so.  The changes are:

runtime/src/arg.c
  Add -E option parsing and environment variable setting.

doc/release/README.executing
  Document the new option.

test/execflags/ferguson/help2.good
test/execflags/shannon/configs/help/basehelp.txt
test/execflags/shannon/help.good
  Update the expected "-h" output.

test/execflags/gbt/dash-E-1-opt.chpl
test/execflags/gbt/dash-E-1-opt.execopts
test/execflags/gbt/dash-E-1-opt.good
test/execflags/gbt/dash-E-1-opt.skipif
test/execflags/gbt/dash-E-2-opts.chpl
test/execflags/gbt/dash-E-2-opts.execopts
test/execflags/gbt/dash-E-2-opts.good
test/execflags/gbt/dash-E-2-opts.skipif
  New unit tests.
Merge branch 'master' of github.com:chapel-lang/chapel into dash-E
Add script to verify copyrights in source files.
Run checkCopyrights.bash in smokeTest.
Add script to prepend copyright with license info to source files.

The util/buildRelease/add_license_to_sources.py script accepts a list of files,
detects the type of comment for each one, and then prepends a comment including
the copyright with license info. The content is stored in a separate file to
make versioning/history easier.
Prepend comment to all sources with copyright and license information.

This uses the new `util/buildRelease/add_license_to_sources.py` script. I ran
this code in bash to tag all of these files:

```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
```

Those find calls were derived from the existing `make/Makefile.release`, which
is called from `util/buildRelease/gen_release`. I did not include the `*.g`
files because none such files exist in the repository.
Remove make/Makefile.release and do not call it from gen_release.

This is no longer needed, since the sources have the comments when they are
checked into the repo.
Builds hello.chpl and blows chunks.
Now runs hello.chpl
This version fixes the problem with varagrs.chpl.
This version passes all primers tests.
Merge remote-tracking branch 'origin/master' into tag-source-files-with-license-comment
Merge branch 'master' into callDefaultConstructors
Fix flattenFunctions.cpp:191 assertion failures by adding .readFE() or .readFF() explicitly in test sources, in lieu of (disabled) statement-level symbol insertion.
Initial support for specifying stdin file in execopts
Using execopts stdin file for knucleotide
Using execopts stdin file for reverse-complement
Adding first cut of curl support, have to fix a problem in qio_channel_revert_unlocked
Merge branch 'master' into curl
Changes through Tuesday mid-day.