Before, executing Get in a file rewound the window offset and
selection to the start of the file.
After this CL, Get preserves the window offset and selection,
where preserve is defined as "the same line number and rune
offset within the line". So if the window started at line 10
before and the selection was line 13 chars 5-7, then that
will still be true after Get, provided the new content is large
enough.
This should help the common situation of plumbing a
compiler error, realizing the window is out of date,
clicking Get, and then losing the positioning from the
plumb operation.
Bad remote file systems can change mtime unexpectedly,
and then there is the problem that git rebase and similar
operations like to change the files and then change them back,
modifying the mtimes but not the content.
Avoid spurious Put errors on both of those by checking file
content.
(False positive "modified since last read" make the real ones
difficult to notice.)
If the mouse was in the tag of the old window,
it was most likely pointing at Del. If bringing up a
new window from below and not moving the mouse
somewhere else, adjust it so that it ends up pointing
at Del in the replacement window's tag too.
This makes it easy to Del a sequence of windows in
a column, from top to bottom.
http://www.youtube.com/watch?v=ET8w6RT6u5M
R=r
http://codereview.appspot.com/6558047
Move libfmt, libutf into subdirectories of lib9.
Add poll-based socket i/o to libthread, so that we can
avoid using multiple procs when possible, thus removing
dependence on crappy pthreads implementations.
Convert samterm, acme to the single-proc libthread.
Bring libcomplete, acme up-to-date w.r.t. Plan 9 distribution.
