Record load averages over 100

Signed-off-by: Florian Forster <octo@collectd.org>
src/utils_mount.h: Add <stdio.h>.

This is required on Solaris 10. Thanks to dannypoo@ for reporting this
problem.

Github: #306
write_riemann plugin: Fix a memory leak.

Attributes were allocated and added to the event but not freed. D'oh!
Thanks to @dch for reporting this!

Github: #307
write_riemann plugin: Really fix a memory leak.

Github: #307
dns plugin: Resume after receiving a PCAP_ERROR from pcap_loop().

If an interface goes down while capturing, libpcap returns PCAP_ERROR.
Handle this case gracefully.

Github: #308
varnish plugin: missing definition in default config
dns plugin: Sleep for an interval before re-trying to read from interface.

Otherwise we'd just have the CPU hogging behavior shifted from libpcap
to collectd …

Github: #308
collectd.conf(5): Fixed documentation for include filter patterns.

The syntax has been changed from a positional argument to using an <Include>
block with additional arguments.
varnish plugin: add missing fields

This commit adds a large number of fields exported by the varnish stats
interface which have not previously been collected. A number are still missing,
as it is not immediately obvious which stat group they should go in:

    accept_fail
    client_drop_late

and, from Varnish 3.X:

    vmods
    n_gzip
    n_gunzip

In addition, there are a number of fields which were added at the end of the 2.X
series, but in the absence of a way of detecting whether we're compiling against
2.0.X or 2.1.X, are necessarily disabled when compiling against 2.X:

    dir_dns_lookups
    dir_dns_failed
    dir_dns_hit
    dir_dns_cache_full
    backend_retry
    fetch_1xx
    fetch_204
    fetch_304
add MeasureResponseCode refs #319
Improve varnish section in manpage.

There previously was no mention of the mandatory <Instance> block.
varnish: hint about missing <Instance> block

The warning when the Collect* configuration options where used outside
of an <Instance> block was confusing. This patch warns the user the same
way the apache plugin does.
varnish plugin: update config docs for new collectors
src/plugin.c: Make plugin_load() idempotent, i.e. don't load plugins twice.

Previously, multiple 'LoadPlugin "foo"' lines would dlopen the same .so file
twice and call its module_register function twice. This would eventually result
in complaints about callbacks with the same name being registered. With this
patch each plugin is only loaded only once, allowing people to write "self
contained" configuration segments.

Thanks to Tim Bunce for suggesting this!

Github: #333
collectd.conf(5): Document the new "LoadPlugin" behavior.

Github: #333
src/plugin.c: Move the perl and python "global" magic to plugin_load().

The config file handling is really not the best place to have this. Also,
the feature I'm working on would have to copy this magic if left in the
config code, and I *really* don't want that.
src/plugin.c: Fix a comment regarding duplicate plugin_load() calls.
src/configfile.c: Add the "AutoLoadPlugin" option.

When enabled, <Plugin ...> blocks will automatically load plugins.
Thanks to Tim Bunce for suggesting this!

Github: #333
Fix modbus segfault / New strategy for connecting

The previous implementation had a reconnection loop which should not
really be necessary. Idea tried here is to check if connection is alive,
and establish it if not. Change was begun because previously connection
would only be attempted as a retry, so on first pass a NULL was handed to
libmodbus which caused segmentation faults reproducibly.

Signed-off-by: Florian Forster <octo@collectd.org>
Cleanup modbus connection if wrong result

Change-Id: I1b7520442d7663d5bc2529369e27e3e858fe2168
Signed-off-by: Florian Forster <octo@collectd.org>