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
Initial support for specifying stdin file in execopts
Using execopts stdin file for knucleotide
Using execopts stdin file for reverse-complement
Changes through Tuesday mid-day.
Merge branch 'master' of github.com:chapel-lang/chapel into REG-TRI
Wednesday updates.
Today's changes.
Ready for unit testing.
Add local blocks to the BlockStmts walked during return path checking

The statements in a local block should be walked in isDefinedAllPaths in the
same way as for plain BlockStmts and do-while BlockStmts.  This gets rid of the
warning in users/ferguson/local-return.chpl, so remove that .future and .bad.
Today's updates.
Rename 4 methods on ModuleSymbol, e.g. getClasses() to getTopLevelClasses(), to emphasize that they only get the top level objects
Extend getTopLevelClasses() etc to work consistently with module initFn at the start of docs() and the start of normalize()
Migrate insertModuleInit from the start of docs() to the start of normalize()
Modify the sources for the .good file on two tests now that the initFn has migrated past docs
Merge branch 'master' of github.com:chapel-lang/chapel into dash-E
Today's updates (so far).
Snapshot:
- update parseArgs() to know whether it's the launcher or user
  executable and whether it's parsing -E options or others
- call parseArgs() early to do -E options in main, later for the rest
- call parseArgs() in the launcher
- Merge the two dash-E tests into one, with two .execopts entries.
Merge branch 'master' of github.com:chapel-lang/chapel into REG-TRI