Show better traceback during payday crash
Merge pull request #3005 from gratipay/payday-tracebacks

show better traceback during payday crash
retire the "making the world better" statement prefix

closes #1659
move privacy options to the privacy section
implement editing "number" on "Account" page
allow profile statements in multiple languages

closes #2669
remove ad-hoc `_clip` function, use `excerpt_intro` instead
fix title
drop unnecessary functions
remove obsolete function
move COUNTRIES constant to i18n module
move the initialization of LOCALE_EN back to i18n module
use an OrderedDict for COUNTRIES
use the data from babel for COUNTRIES instead of duplicating it
add a `languages_2` OrderedDict to locales
restrict statement languages
implement upserting and fetching statements
implement UI for multilingual statements

also refactors some JS code
use the jsEdit generic code for the bitcoin input
use the jsEdit generic code for the username input