Fix ct backend dialyzer warnings

Note that compiling on OTP 17.0, or later, will produce beam files
(specifically lager_trunc_io) that are incompatible with R16B03-1, or
earlier, due to erlang:is_map/1 using a new beam opcode (156). However
if compiled on R16B03-1, or earlier, will produce beams files that are
compatible with 17.0, and later, and maps will be formatted where
supported by the active OTP release.

* Fix unmatched return
* Fix set_loglevel call to store mask in state
* Add common_test to plt for ct:pal spec

The example in "Internal log rotation" includes the tuple
{name, "error.log"}

This apparently should be

{file, "error.log"}

as seen in other config examples in README.md.

lager_common_test_backend

fix issue #215: lager.app env overwrites default handlers

the default handlers defined at lager.app overwrites handlers defined previously by application:set_env(lager, handlers, ...) if lager application is started application:start(lager)

Fixed typo in README.md

Fixed forgotten commas.

Added options parameter to lager:trace_file

Fix compile on Release 17 the right way.

Change a latin1 sequence so it is given as a list of integers. this avoids the problem entirely
since ASCII has the same representation in both latin1 and in utf-8

Use a binary rebar compiled with an older version of Erlang.

It has been compiled with R13B03 and resolves issue #183.

Make tests pass on buildbot more of the time

support disable pretty printing records encountered at compile time

Only discard gen_event notifications on high watermark

Previously all messages were being flushed, which meant that trapped exits
and internal gen_event messaging was also flushed, leading to undefined
behaviour.

closes #198

Fix: correct lager startup in crash_log test

Fixed empty tuple bug in lager:pr/2

Modified unit test to test 0 size tuple case.

Don't use the proplists module when decoding error_logger messages

Add newline to error_msg:error_report lines in crash.log, see #164

pretty printing of nested records

Fix lager_console_backend:is_new_style_console_available() function

Proplist module is a lot slower than lists:keyfind, which is a BIF,
because proplists has to work with 'bare' atoms as well as 2-tuples.

This should marginally improve the throughput when printing many
error_logger messages.

Add xref target, with exclusions

Remove the workaround for the bug when printing empty binaries in W mode

The fix for this was merged in R16 somewhere, so this workaround is no
longer needed, and fixes the EQC test from spotting the divergent
behaviour with io_lib.

See also: http://erlang.org/pipermail/erlang-patches/2012-September/003034.html