Added `update-source-location', which provides keyword-based functional update
for source location representations.
Removed automatic collection-relative printing for source locations.
* unstable/location.ss
Made `quote-srcloc' and its related forms all automatically use source locations
relative to collections and/or planet, where appropriate, and to compute
source locations dynamically if they cannot be made relative.
Removed #:module-source argument from `quote-srcloc'.
Changed `quote-module-path' and `quote-module-name' to use source file name
extensions.
Removed `quote-module-source'. I'm not sure what the use case is for
generating a resolved module path that doesn't correspond to a real module.
* unstable/dirs.ss
Implemented `path->directory-relative-string' for rendering a path to a string
that is relative to one of a list of given directories, with associated
abbreviations for each.
* unstable/scribblings/unstable.scrbl
* unstable/scribblings/srcloc.scrbl
* unstable/scribblings/dirs.scrbl
Documented the above changes.
* scheme/contract/private/provide.ss
* scheme/contract/private/base.ss
Changed contract forms to always blame a module path where appropriate.
Removed use of #:module-source option for `quote-srcloc'.
* setup/private/path-utils.ss
Updated `path->name' to use more general `path->directory-relative-string'.
svn: r18816
