Moved “require("fs")” to the top of livlabot.

The line `var fs = require("fs"), path = require("path-extra");`
appeared again and again throughout the file. Never, in the file, are
`fs` and `path` defined to be anything else than these modules.

We can load the modules once and for all, and use them in the script
without ensuring that they are indeed these modules.
Created a function to create the config directory.

I created a function to create the config directory. Or any directory,
for that matter. It essentially does what was done when loading
“~/.livla/notci.txt”, directory wise: try to create it, and if it fails,
check that the directory already exist.

One difference is that the previous code was not failing if “~/.livla”
existed but was not a directory. This code will.
Created a function to read configuration files.

The `readConfig` function is here to read any file situated in
“~/.livla”. If the file does not exist, it returns an empty string.
`readConfig` ensure that “~/.livla” exists.

`notci` is now loaded with `readConfig`. One difference with the code
before this commit is that `readConfig` does not create the missing
files. So, unless we have something to put in it, “notci.txt” is not
created when we launch the script. However, this file, once loaded, is
only written in, never read. So, this should not cause any problem.
Moved the loading of “notci” into a function.
Added a mean of configuration in “~/.livla/config.json”

And modified the documentation consequently.
Added a link to the lojban wiki in livla README.
`==` should be `===` in `readConfig`
Merge pull request #31 from daeldir/master

Added a configuration file, and some refactoring.