LuaLogging: A simple API to use logging features in Lua

LuaLogging
A simple API to use logging features in Lua. Portuguese version.

## Rolling File appender

The rolling file appender can be used to write log messages to a file. It uses Lua I/O routines to do its job. The rolling file appender rolls over the logfile once it has reached a certain size limit. It also mantains a maximum number of log files.

    function logging.rolling_file(filename, maxFileSize, [maxBackupIndex], [logPattern])

- `filename`:
  The name of the file to be written to.
  If the file cannot be opened for appending the logging request returns nil and an error message.
- `maxFileSize`:
  The max size of the file in bytes. Every time the file reaches this size it will rollover, generating a new clean log file and storing the old log on a filename.n, where n goes from 1 to the configured maxBackupIndex.
  The more recent backup is the one with the lowest n on its filename.
  Eg. test.log.1 (most recent backup)
  test.log.2 (least recent backup)
- `maxBackupIndex`:
  The number of backup files that will be generated. The default value is `1`.
- `logPattern`:
  A pattern can be specified to control how the message is written.
  The default value is `"%date %level %message\n"`.

## Example

    require"logging.rolling_file"

    local logger = logging.rolling_file("test.log", 1024, 5, "%Y-%m-%d")

    logger:info("logging.file test")
    logger:debug("debugging...")
    logger:error("error!")