Merged from trunk 5533:5549

Merged from trunk 5533:5549

For bug #161422, make slot collisions non-fatal in cases where an
invalid depgraph is acceptable (--fetchonly, for example).

Don't allow slot collision nodes to block other packages since blocker
validation is only able to account for one package per slot.

Rename depgraph._invalid_depgraph_is_acceptable() to
_accept_collisions() for a better description.

Add a bit of path mangling to allow deeper tests (WarnerBro)

remove bogs test dir, add portage_versions (WarnerBro)

edit test-notes (WarnerBro) (duh! you can do better)

more test re-arranging as Alec can't read what functions are in what
files (WarnerBro)

Remove / character from module names.

Remove RESTRICT=sandbox docs until bug #161045 is resolved (genone)

Update CCACHE docs, patch by Ryan Hill (bug #156865) (genone)

Add 'stricter' description, misc typo fixes, patch by Max Lorenz (bug
#153755) (genone)

Rename 'Last Sync' to 'Timestamp of tree' to clarify the meaning (bug
#150051) (genone)

Don't escape strings in PortageException as that breaks newline handling
(bug 147785) (genone)

More portage_util tests (WarnerBro)

Extend ignore filter for grablines (bug #144445) (genone)

add stack_lists checks (WarnerBro)

svn path=/main/branches/prefix/; revision=5616