Some more g_source_remove warning fixes

- http_incoming_data calling itself
- jabber_bs_free_transfer calling jabber_si_free_transfer
dcc: Fix some invalid memory accesses reported by ASAN

ASAN <3
Merging two other Debian fixes in preparation for a 3.2.2-1 upload.
3.2.2-1. Minor change, removed very old compatibility kludge.
Debian bug #764181: Accidentally had an LGPL header in a bunch of files.
Replaced them with GPL headers where possible. OSCAR and Twitter modules
can't be relicenced though, so add an LGPL blurb to debian/copyright.
doc/AUTHORS updated to the current state of things.
cmd_otr_keygen: improve argument parsing
Require libotr 4.0.0 instead of the version it was compiled with

With the OTRL_INIT macro, building against 4.1.0 results in bitlbee
refusing to run if the installed libotr version is 4.0.0, even though
they are compatible and we don't use the new exposed APIs of 4.1.0
README: Remove workflow notes
README: coverity badge, pull requests, external workflow notes
Revert "Require libotr 4.0.0 instead of the version it was compiled with"

This reverts commit 09a04ac975270a7433943b4113cbb220d4d16ed8.

It got rejected upstream (this is not our problem), and tbh I agree.
msn: update ABService ApplicationId to WLM 2012 to fix login

The previous ApplicationId was from WLM 2008 (8.5)
travis: Don't require signatures in dpkg-buildpackage

It started failing recently due to an update on their side.

And signing debs that are just going to be thrown away is pointless.
msn: Update ApplicationId again to one used by skype

Because why not
msn_buddy_ask: only ask to add if contact is in pending list

Previously it asked if they were in pending/reverse but not allow/block.
In theory that would fix inconsistent states. And in practice... nope.
msn: add 'allow' role if contact has neither block nor allow

This workarounds the problems of showing as offline to other contacts,
by sending ADL with role 3 (FL+AL) instead of just 1 (FL, no AL or BL)
dear travis: stop breaking randomly. thanks
configure: --asan=1 parameter for AddressSanitizer

Requires gcc >=4.8 or clang >=3.1

AddressSanitizer (ASan) is a fast memory error detector. See also:

https://code.google.com/p/address-sanitizer/wiki/AddressSanitizer
Revert "Twitter search channels" to sync with master

This reverts commit f370af0a95ab803486705d32df859fc947140a12.

It never landed in master because it 'leaks' contacts, as in they never
get removed from the channel/blist until the account gets removed, which
becomes a big issue with high activity hashtags.

Sending it back to review, will apply again once it's fixed.
Use glib functions for base64 decoding/encoding

This fixes several coverity warnings about 'tainted data index sink' and
a fixme about thread safety in the old base64_decode implementation.

Had to adapt the code that used base64_encode_real:

 - oauth.c: different character set order, but it's for the nonce so it
   doesn't matter
 - libyahoo2.c: used as part of the auth, changes "+/=" into "._-".
   Fixed by encoding first the usual way through glib, then replacing.