Make flog an importable package

[chaudum]

There are cases where you want to generate log lines directly in your application. Therefore it is necessary to make the module github.com/mingrammer/flog importable in other projects.

Moving the code that should be importable out of the main package into its own will allow others to use import flog.

Signed-off-by: Christian Haudum [email protected]

[mingrammer]

Please resolve the conflict