make it possible to set the default search path for the attach and load commands

[williamstein]

This was requested by nihilalienumcredo in sage-support. He wants to be able to do

sage: set_attach_path('/foo/bar/')
sage: attach file.sage

and have it work from any location so long as /foo/bar/file.sage exists.

Component: misc

Issue created by migration from https://trac.sagemath.org/ticket/5169

[sagetrac-mabshoff]

comment:1

See the thread at

http://sage.math.washington.edu/home/malb/spkgs/libm4ri-20090128.spkg

for details.

Cheers,

Michael

[sagetrac-mabshoff]

comment:2

Oops, see the thread at

http://groups.google.com/group/sage-support/t/37795251481402a1

for details.

Note to self: First check post, then hit button :)

Cheers,

Michael

[qed777]

comment:4

Closely related: #378, #1484

[qed777]

comment:5

I'm closing this as a duplicate of !#378.