Initial "argSigil" support.

This uses Perl-ish sigils to declare the type of argument expected
by executables.  Sigils can be one of "$@%*", to signify string,
array, object, or any as the expected arg type.

This helps remove some boilerplate type checking from executables,
and makes it easier to parse shell input in an intelligent way.
Fix jsDirectory..install of exes with sigils in the name.

Also added some sanity checking to make diagnosis easier in the
future.
Fix createRootFrame, set view content size

* Make createRootFrame return the current root frame if there is
  one.
* Ensure that the view contents are sized to the whole view
  rectangle.
Merge remote-tracking branch 'origin/master' into mine_file
Improve error messages.