Doc improvements from LA Clojure Meetup discussion

[seancorfield]

• maybe move legacy 1.x stuff to lower down the readme since no one needs to know that now?
• most clauses expect a sequence -- say vector (even tho' it can be a list)
• such as :set -- not immediately obvious there's a connection to update!
• quoted symbolic form -- doesn't work with the ' in the web app
  • it's also not obvious in getting started why this feature exists
• with a parameter of 0 (not clear that this is the result) -- move nil inline ahead?
• inline with single argument -- no, supports multiple elements
• % syntax should use keywords or quoted symbols
• (sql/format {:select [:x [:y :d] [:%z.e] [:%z.f :g]]}) -- don't need [] on %z.e here
• (param x) doesn't work (symbolic form), nor does :params with symbols -- both should
• examples of composite/over -- should have example of/links to other helpers' equivalents
• dialects: mysql stropping isn't readable!
• enable quoting globally via set-dialect! -- example or link!