updated errors list and merged latest contributions made to accounts-entry

Hi @softwarerero !

I've found a bit of time and managed to to the famous merge I promised time ago.
I've made a fresh search of `new Meteor.Error` across the devel branch of meteor packages and updated all the keys accordingly. Moreover I've marked with `#->` the lines with keys not yet translated. Keys starting with `#', differently, are impossible to translate in a easy way (because of *parameters*) or not likely to appear in a deployed application.

What do you think about this? Do you agree to move here also standard text in addition to errors?
In case you approve it, we'd better cc all other contributors to kindly ask to review the changes and complete this awesome work!

...there might be room also for other discussions about, e.g., titleized vs. lower case translations not to have the number of keys bloating and letting every one processing them as wished
or, pherhaps, `XXX` instead of `accounts.XXX` and `error.YYY` instead of `error.accounts.YYY` for keys?

Let me know!
Many tanks,
Luca