Write good readme and maybe even tutorial

[chshersh]

Current README doesn't explains how to use log-warper which is bad. This README should be written. Too much effort was put into log-warper. So we must try to make this library more production-ready.

[chshersh]

Now we have HowTo.md with example of how to configure logging system and replace your putStrLn with logInfo. But this is not the whole tutorial. Here I will outline remaining parts:

Plan

• [x] How To use log-warper in your project: resolved in PR #58
• [x] How to use pure logging LHS and MD example
• [x] README.md updated with all features of log-warper
• [ ] Reference/FAQ section

In this message I will describe in more details what should be covered in above sections. This list might not be complete though...

Features

log-warper provides next features:

1. Colored logging output.
2. Hierarchical logger names.
3. Different severity levels of messages with the ability to configure Set of severities.
4. All* (well, almost) configuration can be described in .yaml file.
5. Pure logging.
6. Flexible and easy creation of LoggerConfig using monoidal builders and lenses.
7. In-Memory logging with the ability to acquire last N megabytes of logs from in-memory cache.
8. Monadic interface for logging.
9. Logger rotation.

FAQ

1. How can I redirect all output to stderr?
2. How can I disable only Error messages for my logger?
3. How can I show ThreadId inside log message?
4. How to easily disable terminal output?
5. How can I enable messages with severity Info and higher?
6. How can I log inside functions like forkIO?
7. How can I easily log exceptions without throwing them?
8. How should I configure logging: through code or through .yaml file?