[plt-scheme] 350.2

MzScheme and MrEd are now version 350.2 in the SVN repository trunk.

Changes:

 * Changed the module name resolver protocol so that the resolver is
   required to accept 1, 3, and 4 arguments; the new 4-argument mode
   supports resolving a module path without loading the module.

 * Changed `namespace-attach-module' and `namespace-unprotect-module'
   to accept quoted module paths, instead of only symbolic names. Using
   the new module name resolver protocol, they can resolve the module
   name without loading a module.

 * Fixed avoidable overflow and underflow in `magnitude' and `/' for
   inexact complex numbers.

 * Fixed a bug related to sharing in nested continuations.

Matthew