FIX. log writer names.
Improve date format.
Implement smtp writer
Sending message as attached text file
Add XXX_dump functions to log object

User provide dump function to serialize complex objects.
LOG.debug(dump(...)) -- dump calls every time
LOG.debug_dump(dump, ...) -- dump calls only if debug level is set

``` lua
local pretty = require "pl.pretty"
local dump = function(msg, var) return msg .. '\n' .. pretty.write(var) end
...
LOG.debug_dump(dump,"try connect to server ...",context)
```
In Log ctor max log level parameter can be a string

LOG = require"log".new('DEBUG',....
Fix. Log.set_level do not support string as parameter
Add new log levels: EMERGENCY, ALERT and TRACE
Rename EMERGENCY to EMERG
Add syslog formatter
Add stdout/stderr writers
Add new concept LogFormat

XXX_dump(dump_fn, ...)
Logger can not pass output dump_fn to formatter. (formatter based on string.format and dump_fn return "%s").

Now creates 2 formatters: log_format and msg_format.
msg_format create only message. This formatter calls from logger.
log_format create result log record. This formatter calls from writers.

examples of msg_format: concat, string.fromat
examples of log_format: default, syslog, proxy
Fix smtp writer.
Add getters for log writer and log format
lakefile support Lua 5.2.
Lua 5.2 compatibility
Add. Supports ansicolors to writer.console.color.
Fix. If no color library then writer.console.color use writer.console.
Add. Supports new version of ansicolors
Explicit load std lua modules.
Add dump and log methods to logger object.
Usage:
log.dumb('fatal', debug.traceback, 'do work', 2)
log.log(log.LVL.INFO, 'some message')