Minor fixes for wlib's "ar" compatibility mode

This pull request fixes two issues encountered with wlib's AR mode.  Specifically:

1.  Switching to AR mode, aside from renaming wlib, relies on WLIB$AR being defined as an environment variable.  However, **WLIB$AR** is not a valid environment variable in bash, which can be a major problem on GNU/Linux.  I've added **WLIB_AR** as another environment variable to trigger AR mode.  **WLIB$AR** remains present for compatibility.

2.  AR mode did not seem to work anyways.  For example, the following command would fail:

`ar -r -c libcollection.a objs/first.o`

Wlib would fail with the above command with "Error! Invalid option '-l'" because wlib is mishandling the *operation*s specified in the command line.  Specifically, it was parsing each argument of the command line individually, and the *operation* set by each argument did not persist to the next argument parse call.  Because the *operation* did not persist, the parser incorrectly treats the argument "libcollection.a" as yet another option.