Fix various problems detected by Clang 3.4.

- cidr.cpp: remove inverted_bits; unused since 9fad3ecb9215a0034bf407f192926b04cb5efaed.
- cmd_stats.cpp: remove needless inversion and comparison to 0.
- inspircd.cpp: remove needless comparison to 0.
- socket.cpp: remove all_zero; unused since 03a1bf15b1da7643b237c22db1a478916a976ccf.
socketengine_select Reset the values in the timeval struct on *nix before select()
Merge pull request #772 from SaberUK/insp20+llvm34

Fix various problems detected by Clang 3.4.
Fix /who on opers incorrectly showing +i opers to
users without the privilege to see them, introduced in
b328aad53b044bd9cf9720dfed216b0ee61c8e31
Fix Solaris not being able to find modules without pkg-config.
Fix build problem on Solaris

-rpath only takes one dash
Fixes the Solaris build \o/

'''
<fraggeln> SaberUK: http://m.theo.nu/jenkins/job/InspIRCd-2.0/435/label=solaris/console <--
<fraggeln> do you have any clue on why?
<@Shutter> Hmm. Where did that extra - come from.
<fraggeln> Shutter: no idea :)
[...]
<fraggeln> Shutter: sub make_rpath($;$) <-- in make/utilities.pm
<fraggeln> thats where that extra - is'''
Merge pull request #783 from SaberUK/insp20+solaris-hates-posix

Fix Solaris not being able to find modules without pkg-config.
Merge pull request #784 from ShutterQuick/patch-1

Fix build problem on Solaris
Fix NULL dereference on rehash when there is a fatal error in the configuration of connect classes

Fixes issue #780 reported by @JDowny
m_spanningtree Don't send snotices to servers about remote servers splitting

The snotice is sent to opers when the SQUIT is processed by their server
m_spanningtree Do pointer comparison before deleting one of the pointers in TreeSocket::Squit()

While the previous code worked fine in practice, it was incorrect in theory
Improve detection for non-cidr masks to prevent unwanted matches

Fixes issue #762 reported by @neoinr
cmd_names Allow opers having the channels/auspex priv to view the NAMES list of +s channels from outside

A version of the check removed by this commit is in Channel::UserList() which takes the priv into account

Discovered by @Cronus89
Backport "Refactor Channel::UserList() to use std::string"

This gets rid of questionable snprintf() usage, reported by @hifi

Backported commit: 8a06d54076551387f83a29360478ee6605e241b6
Fix NAMES list getting truncated on servers having an excessively long server name
m_operprefix Don't set +y on the oper if hideoper is being unset due to deopering

Fixes issue #801 reported by @UselessOper
m_httpd Fix typo noticed by @SaberUK
m_globalload Don't pass a callback to ModuleManager::Reload() if reloading m_globalload
m_watch Validate targ before use, noticed while rewriting m_watch for 2.2
Major example configuration and helpop update

Big thanks to @m4z (#621) and @Robby- (#630) who contributed a lot to this