ReadMe: update syntax, sensible intro for newbies, FAQ

[Athari]

Update ReadMe to a more sensible state:

1. Get rid of obsolete string lambda garbage. Cast arrays to objects. Make the code pretty, not scary mess it is now.
2. Explain basics like what from does, how to chain, how to iterate (come on man, you copypasted that on StackOverflow 10 times already). Literally anything is better than what ReadMe contains now.
3. Add FAQ with common mistakes like trying to replace ORM with YaLinqo, multiple iterations over a sequence, comparisions etc. Check issues here and on SO.
4. Links to SO maybe? That stupid "opinionated" question would be a good fit.