Fix the remaining case in which getCString:maxLength:encoding is not checked for returning NO before using the result.
Allow disabling of specific levels per-logger.

My team's usage of LumberJack had the following setup:

- four loggers, `DDTTYLogger` and `DDFileLogger,` a crash logger, and an
  analytics logger
- globally-defined ddLogLevel = `LOG_LEVEL_DEBUG`

Our file logger is added with `LOG_LEVEL_INFO.`
Our TTY logger is added with `LOG_LEVEL_DEBUG.`

We use "INFO" events HEAVILY, as they are placed in the file logger and
crash logger to help us know everything that happened leading up to a
bug.

As a requirement, The file logger CANNOT log DEBUG events.

At the same time, because we have such a high volume of INFO events, it
is challenging to see any of the `DEBUG` events in the TTY logger.

We need to be configure our `DDTTYLogger` to at the DEBUG level, but omit `INFO` events.

Essentially: `[DDLog addLogger:ttyLogger withLogLevel:(LOG_LEVEL_DEBUG & (~LOG_FLAG_INFO)];`

However, this isn't possible in the current implementation of
`+[DDLogger lt_log]`

When iterating through registered loggers, `lt_log:`
performs the check, "if (logMessage->logFlag > loggerNode.logLevel) continue;"

Because our TTY logger's highest-set bit is `LOG_FLAG_DEBUG`, all info
events are processed, even though we've unset the `LOG_FLAG_INFO` event.

My proposed change configures `lt_log:` to examine whether a `DDLogMessage`'s
specific `LOG_FLAG_..*` is set in `loggerNode->logLevel`.
Check env and locale
Set language to en_US.UTF-8
Merge pull request #204 from matt-holden/per-logger-bitmasks

Allow disabling of specific levels per-logger.
Fix Podfile.lock
DDFileLogger: using CFBundleIdentifier as a log filename prefix on both OS X and iOS.

This fix #200.
Merge pull request #206 from dvor/ddfilelogger-fixing-bug-with-app-name

DDFileLogger: using CFBundleIdentifier as a log filename prefix on both OS X and iOS.
If the appName can’t be interpreted as UTF8, use “<UnnamedApp>” as the appName.
Fixed whitespace to match surrounding code
Merge pull request #205 from rivera-ernesto/fix_travis

Fix Travis
DDFileLogger: adding ability to set custom log filename by overriding appropriate methods
DDFileLogger: updating outdated comments
Merge pull request #202 from evands/static-analysis-security-fixes

A fix from a security static analysis
Merge pull request #208 from dvor/ddfilelogger-custom-logfile-format

Ddfilelogger custom logfile format
Bumped version to 1.8.0
Add a Bitdeli badge to README
Merge pull request #209 from bitdeli-chef/master

Add a Bitdeli Badge to README
More useful to log the errno value?
Use strerror()