edited awkward phrasing. changed 'local copies' to 'cache locally'.

At least on my computer (running Fedora Linux and Darktable 1.4.2), the
button in Selected Images panel in lighttable mode is labeled 'cache
locally', not 'local copies', so I changed the reference in the manual
page here to be more consistent.
Merge branch 'master' of https://github.com/darktable-org/darktable into clarifying-text-in-user-manual
further tweaking of prose in localcopies.xml

Following the discussion
[here](http://www.darktable.org/redmine/issues/9955)
I changed my "local cache" edits back to "local copies." The feature
name change should be reflected in the application source too.

I changed some references to "external storage" to merely "main
storage" and the like, because I think the use case for this feature
applies to any sort of storage that would be impractical to carry
around, not just to RAID NAS.
edited prose for readability. added some extra information about feature.

A couple times I changed "multiple images" to "one or more images,"
because the rating and labeling methods for multiple images work just
as well for single images.
fixing a few things I missed.
minor typography update: changed ` - ` to actual emdash (`&mdash;`).
edited for clarity and readability.
Cleanup formatting and add partial match warning
Remove useless make/model double arguments
Add a comment about removing black & maximum
Fix the names to silence partial matching warning
Use a more idiomatic expression
Clarify comment
Match the new format of adobe_coeff.c
Merge pull request #567 from pedrocr/cleanup-adobe_coeff

Cleanup adobe_coeff.c
Revert "Clarify comment"

This reverts commit c3e5f6deb5fead2586b6f230811b5fb22d0a66c7.
Revert "Add a comment about removing black & maximum"

This reverts commit f0c9d082c8a8a820fc814851361df21028a19f3f.
adobe_coeffs: Canon EOS 350D/400D DIGITAL full match
tools: mangle FinePix too
Remove inadvertently added file