Steal more test-lib.sh updates from git

Steal more test-lib.sh updates from git

This patch incorporates the updates that were made to git's
test-lib.sh from revision v1.2.2-66-g6643688 up to revision
v1.5.5-67-g9a49e00. A few manual adjustments had to be made -- for
example, the StGit tests assume that the repository starts out with an
initial commit, and there's no need to try to get hold of a git binary
other than the one reachable via $PATH. And the test_must_fail helper
function is not that useful to us, since a crashing Python program
won't kill the entire Python interpreter.

The main improvement is that the test script output is now in color!

Shortlog of the imported changes:

  Alex Riesen (2):
        Fix permissions on test scripts
        Do no colorify test output if stdout is not a terminal

  Christian Couder (1):
        Trace into a file or an open fd and refactor tracing code.

  Clemens Buchacher (1):
        http-push: add regression tests

  Eric Wong (3):
        tests: Set EDITOR=: and VISUAL=: globally
        test-lib: quiet down init-db output for tests
        Update tests to use test-chmtime

  Gerrit Pape (1):
        Set $HOME for selftests

  Jeff King (3):
        fix config reading in tests
        use build-time SHELL_PATH in test scripts
        add test_cmp function for test scripts

  Johannes Schindelin (2):
        Introduce GIT_TEMPLATE_DIR
        Make tests independent of global config files

  Johannes Sixt (1):
        test-lib.sh: A command dying due to a signal is an unexpected failure.

  Josh Triplett (1):
        Fall back to $EMAIL for missing GIT_AUTHOR_EMAIL and GIT_COMMITTER_EMAIL

  Junio C Hamano (26):
        Perl interface: make testsuite work again.
        Perly Git: make sure we do test the freshly built one.
        test-lib: unset GIT_TRACE
        Merge branch 'ml/trace'
        Merge branch 'master' into pb/gitpm
        Deprecate merge-recursive.py
        Merge branch 'jc/gitpm'
        remove merge-recursive-old
        fix testsuite: make sure they use templates freshly built from the source
        Revert "fix testsuite: make sure they use templates freshly built from the source"
        GIT_SKIP_TESTS: allow users to omit tests that are known to break
        t5400 send-pack test: try a bit more nontrivial transfer.
        Fix timestamp for test-tick
        t/test-lib.sh: Protect ourselves from common misconfiguration
        War on whitespace
        Merge branch 'ei/worktree+filter'
        Unset GIT_EDITOR while running tests.
        Sane use of test_expect_failure
        test: reword the final message of tests with known breakages
        tests: introduce test_must_fail
        Merge branch 'cb/http-test'
        tests: introduce test_must_fail
        test-lib: fix TERM to dumb for test repeatability
        Merge branch 'maint'
        Test: catch if trash cannot be removed
        test_must_fail: 129 is a valid error code from usage()

  Martin Waitz (1):
        test-lib: separate individual test better in verbose mode.

  Matthias Lederhofer (1):
        introduce GIT_WORK_TREE to specify the work tree

  Michele Ballabio (2):
        test-lib.sh: move error line after error() declaration
        Fix typo in a comment in t/test-lib.sh

  Nicolas Pitre (1):
        use 'init' instead of 'init-db' for shipped docs and tools

  Petr Baudis (1):
        Use $GITPERLLIB instead of $RUNNING_GIT_TESTS and centralize @INC munging

  Pierre Habouzit (2):
        Add some fancy colors in the test library when terminal supports it.
        Support a --quiet option in the test-suite.

  Robin Rosenberg (1):
        Quote arguments to tr in test-lib

  Shawn O. Pearce (1):
        Default GIT_MERGE_VERBOSITY to 5 during tests.

Signed-off-by: Karl Hasselström <kha@treskal.com>