Refactoring of the russian translation: Functional programming

[yau-ref]

I've made a full refactoring of the Functional Programming chapter for the russian readers:

• Fixed some semantic mistakes
• Eliminated style issues caused by automated translation
• Suggested better translation for some terms
• Improoved readability. The style now is more native for russian language
• A bunch of minor mistakes

Love. Peace. Scala

[caniszczyk]

Sweet! Is there a pull request?

[yau-ref]

Yes, I'll attach it in a couple of minutes

[yau-ref]

I haven't found a well-working way to attach it to this issue, so https://github.com/twitter/effectivescala/pull/43