Directories created with default mode 0755 with ExtUtils::Install

Hello,

ExtUtils::Install creates directries with 0755 by default, ditto for
ExtUtils::MM_Any (blib directories). Probably, there should be a way to
override the default directory creation mode. Alternatively, the module
could allow user's umask take the precedence.

Please let me know what do you think.

Thanks. Rajesh