Add versioned NM_DEPRECATED_IN_* and NM_AVAILABLE_IN_* macros, and tag
new/deprecated functions accordingly. (All currently-deprecated
functions are assumed to have been deprecated in 0.9.10.)

Add NM_VERSION_MIN_REQUIRED and NM_VERSION_MAX_ALLOWED macros which
can be set to determine which versions will cause warnings.

With the current settings, external consumers of the
libnm-util/libnm-glib APIs will have MIN_REQUIRED and MAX_ALLOWED both
set to NM_VERSION_0_9_8 by default, meaning they will get warnings
about functions added in 0.9.10. NM internally sets
NM_VERSION_MAX_ALLOWED to NM_VERSION_NEXT_STABLE to ensure that it is
always allowed to use all APIs.

Rather than explicitly passing around a UID and a flag saying whether
or not it's relevant.

(This also fixes a bug where the wrong UID was being recorded in
nm-settings-connection.c::auth_start(), which caused problems such as
agent-owned secrets not getting saved because of a perceived UID
mismatch.)

https://bugzilla.gnome.org/show_bug.cgi?id=710505

Unfortunately, $(AM_CPPFLAGS) gets overridden by per-target _CPPFLAGS
variables, which $(INCLUDES) did not, so this requires some additional
changes.

In most places, I have just gotten rid of the per-target _CPPFLAGS
variables; in directories with a single target, the per-target
variable is unnecessary, and in directories with multiple targets, the
per-target variable is often undesirable, since it forces some files
to be compiled twice, even though there ends up being no difference
between the two files.

Signed-off-by: Thomas Haller <thaller@redhat.com>

Add a "monitor-connection-files" config option, which can be set to
"false" to disable automatic reloading of connections on file change.

To go with this, add a new ReloadConnections method on
o.fd.NM.Settings that can be used to manually reload connections, and
add an nm-cli command to call it.

ifcfg-rh didn't let you unmanage an InfiniBand device by hardware
address because it was recording the hardware address with uppercase
letters, while nm_match_spec_hwaddr() required lowercase. Fix this by
making nm_match_spec_hwaddr() match case-insensitively (and remove the
manual lowercasing that several other places were doing to work around
this.)

keyfile didn't let you unmanage an InfiniBand device by hardware
address because it only accepted ARPHRD_ETHER hardware addresses. Fix
that by using nm_utils_hwaddr_valid() instead.

We don't always want to immediately write new connections to disk, to
facilitate "runtime" or "temporary" connections where an interface's
runtime config isn't backed by on-disk config.  Also, just because
an interface's configuration is changed doesn't necessarily mean
that new configuration should be written to disk either.

Add D-Bus methods for adding new connections and for updating existing
connections that don't immediately save the connection to disk.

Also add infrastructure to indicate to plugins that the new connection
shouldn't be immediately saved if the connection was added with the
new method.

Use the new NMConnection 'changed' signal to mark connections
as dirty/unsaved, and reset that when they get flushed to disk.
Previously, the 'Updated' signal was emitted only when the
connection was changed and flushed to disk, but now we have
more granular needs, and the signal is emitted whenever the
connection actually *is* changed, regardless of whether its
flushed to disk or not.

They can just call nm_config_get() now to get the config, and
nm_config_get_path() to get its path.