Fixes the implementation of magit-dired-jump

The original implementation broke `C-x C-j`'s natural behavior. The
status buffer is naturally associated with the root of the git
directory. This natural behavior is reinstated for any location in the
buffer not associated with a more specific file.
magit-log-oneline-re: add missing statuses

The regex was missing the values for the cases:

 - "U" for a good, untrusted signature, and;

 - "N" for no signature.

Without this, the log buffer in short mode and with
`magit-log-show-gpg-status` evaluating to true, would unconditionally
show the GPG signature status, author and relative date in the message
line as output by git.
make displaying tags line in status buffers a choice

Move the code that collects information about the two closest tags and
displays them info new function `magit-insert-status-tags-line' and add
new option `magit-status-insert-tags-line' to control whether that
function should actually do anything or return immediately.
add option to choose whether HEAD/tag is subject in tags line

Add new option `magit-status-tags-line-subject' which controls whether
each tag or HEAD is considered the subject in the two imaginary
sentences the tags line in status buffers imply.
magit-rev-diff-count: support git < 1.7.2
Ignore whitespace in magit-blame-mode.

Add defcustom magit-blame-ignore-whitespace.
Merge branch 'magit-blame-ignore-whitespace'
Merge branch 'feature/improve-tags-line'
Merge branch 'fixing-dired-jump'
Merge branch 'afrepues-master'
don't run tests on travis, still build

Don't run tests (make test) on travis but still build the libraries
(make core contrib).  The tests have been failing for a long time on
travis when it was under high load and nobody has stepped up to fix
this issue.

It is better to not run the tests (they don't cover much anyway).
The alternative of just ignoring failure would mean we would also
not notice build failures.
magit-git-dir: use file-name-as-directory

instead of (concat ... "/").
Merge branch 'fix-diff-count'
Merge branch 'master' into next