Add lager deps and various formatting

* Add lager as relx deps and add lager info macros
* RIP tabs
* RIP trailing whitespaces
* Change indentation of .erl files to default 4 whitespaces
* Change indentation of .html files to default 2 whitespaces
* Minor cleanup of .css file indentation
* Remove trailing newlines
* Remove unnecessary newlines
Extend .gitignore for Erlang and Emacs
Add postgresql integration and initial contract handling

* Add epgsql and poolboy deps
* Add poolboy worker callback module and supervisor
* Add initial poolboy postgresql configs in app module
* Add enter-contract JSON API
* Add contract handling module with enter-contract API validation
* Add initial modules for Postgres handling
* Add Postgres bootstrap scripts
* Add jiffy as dep for JSON decoding
Merge branch 'features/api2_and_postgres'

* features/api2_and_postgres:
  Add postgresql integration and initial contract handling
  Extend .gitignore for Erlang and Emacs
BitcoinJS-lib added, with example hello-js.html
Mechanism and stubs for all pages in the MVP #2 flow:
 * index.html
 * about.html
 * intro.html
 * bets.html
 * bet.html
 * flow.html
 * prep.html
 * pend.html
 * sign.html
 * followup.html
 * status.html
 * events.html
 * cashout.html
 * wrapup.html