build: Add --enable-installed-tests

See https://live.gnome.org/GnomeGoals/InstalledTests for more
information.

It's still possible to run `make check` with locally uninstalled tests.
build: Remove INCLUDES

It has been replaced by AM_CPPFLAGS for a while.
build: Add ltp 1.10 to the whitelist
Tajik updated
Tajik translation updated
build: Add configure option to enable -Bsymbolic

We should always compile with -Bsymbolic enabled to avoid intra-library
PLT jumps.

https://bugzilla.gnome.org/show_bug.cgi?id=703734
Use new macros when compiling against new GLib

If we're being compiled against a newer version of GLib, we should use
the new macros that add instance private data.

Since this is a stable branch, we cannot bump the GLib requirement; so
we use version checks to conditionally compile the new code.
Added Friulian translation
Bump to 0.17.1

Start a new development cycle.
Require GLib >= 2.37.6

We're going to need the latest snapshot.
tests: Use the new TAP support in GTest

Instead of using the old GLib test harness, we should use the newly
added TAP support and the TAP driver inside autotools.
path: Remove unused variable
Remove compile time GLib version check

We depend on a new version of GLib, so we can remove a bunch of old
version checks.
parser: Drop a pointless macro

The JSON_PARSER_GET_PRIVATE macro is pointless, now that we use the new
version of GLib.
parser: Use the proper GLib API to find test data files

Instead of our homegrown solution. This should fix the regression in the
installed tests case.

Original patch by: Colin Walters <walters@verbum.org>
parser: Fix all occurances of TESTS_DATA_DIR

And use g_test_build_filename().
Drop some more pointless GET_PRIVATE macros

We can use the autogenerated get_instance_private() function.
MSVC Builds: Drop Unneeded Defines

...since we are using GLib APIs to locate test data files since
commit b8baa2a0
MSVC Builds: Build the invalid test program

Add project files to build the "invalid" test program.
Visual C++ Builds: Use Custom Build Rules

...so that the json-glib.def file can be regenerated as automatically
when the json-glib.symbols file is updated, and the json-glib.def can be
automatically deleted on a "clean" request.

Also drop some unneeded items from the property sheets.