Replace isletter.m, ishghandle.m with DEFALIAS?

[Rik]

12/31/10

John,

The two functions in the Subject line are really just aliases for isalpha
and ishandle respectively.  Is there any reason why we shouldn't delete the
.m script files and just use DEFALIAS in the C++ source code?

This is the strategy already followed for islogical/isbool,
system/shell_cmd, and quit/exit.  All that is required is to add an extra
@deftypefnx line that documents that the function can be called under its
other name.

--Rik