doc: clarify that cp by default doesn't adjust existing file perms

* doc/coreutils.texi (cp invocation): Mention explicitly what
happens to permissions of existing files when -p is not specified.
Fixes http://bugs.gnu.org/14972
doc: use semicolon instead of period in option descriptions

Also do not end option descriptions with a period, properly indent
continuation lines, and make some tiny clarifications.

* src/du.c (usage): Lowercase after semicolon.
* src/ls.c (usage): Semicolons instead of periods, small rephrasing
and two hyphens for clarity, proper indentation.
* src/mktemp.c (usage): Semicolons and lowercase.
* src/od.c (usage): Semicolons.
* src/ptx.c (usage): Use the standard phrase, clarify default option.
* src/setuidgid.c (usage): Properly indent continuation line.
* src/split.c (usage): Semicolons, lowercase, no final period.
* src/stat.c (usage): Semicolons, lowercase.
* src/tail.c (usage): Proper indentation, one shorter rephrasing,
semicolons, no final periods.
* src/timeout.c (usage): Properly indent, semicolons, no final periods.
Fixes http://bugs.gnu.org/14976
maint: update copyright year number ranges of numfmt sources

Run "make update-copyright".

* src/numfmt.c: Update copyright year number range.  This file has
obviously been added to coreutils after and without the annual update.
* tests/misc/numfmt.pl: Likewise.
doc: clarify that uniq -d outputs a single entry per group

* src/uniq.c (usage): Clarify the -d option.
Fixes http://bugs.gnu.org/14996
doc: more semicolons instead of periods in option descriptions

Also slightly rephrase some descriptions for extra clarity, and
add more consistent indentation.

* src/df.c (usage): Semicolon, no final period.
* src/du.c (usage): Likewise, plus indentation and clarifying words.
* src/ls.c (usage): Semicolon, rephrasings, added parentheses for
clarity, indentation.
* src/rm.c (usage): Semicolons.
* src/tail.c (usage): Adjust -f description to prefer explanatory
language instead of option syntax.
doc: fix typo in description of df

* doc/coreutils.texi (df invocation): s/pseude/pseudo/
* THANKS.in (Filipus Klutiero): Remove entry, now that it will be
automatically included in the generated THANKS file.
Fixes http://bugs.gnu.org/15041
doc: use more modern file system type examples in df description

* doc/coreutils.texi (df invocation): In the example list of common
file system types, exchange the entries which are not so common
anymore (4.2, ufs, efs, hsfs, pcfs) by far more prominent ones
(ext2, ext3, ext4, xfs, btrfs, iso9660, ntfs, fat).
doc: clarify when seq ends

* doc/coreutils.texi (seq invocation): Add a sentence clarifying
that seq terminates when LAST becomes smaller than the current number
plus INCREMENT.
* src/seq.c (usage): Likewise.
Fixes http://bugs.gnu.org/15068