[UPDATE] Allow deletion of accounts

    Updated backend and theme to be able to deal with deleted accounts

    * Backends will skip any users that have no account_id associated with
      their shares
    * Updated round stats theme to show users as unknown if none can be found

    This will not fully address the issue of account deletion but at least
    wont break the system anymore.
Move from XML-RPC to JSON-RPC.
Update 000_base_structure.sql

Small hiccup with a new installation, importing the SQL.
Small human error fix.
Merge pull request #1270 from drainx/patch-1

Update 000_base_structure.sql
[FIX] Registration password lenght, API class default time
Merge branch 'next' of https://github.com/TheSerapher/php-mpos into next
[ADDED] Address validation script

Will allow admins to run a validateaddress check via RPC calls against
the coind for all currently available users in the accounts table.

* UNSET for users without a coin_address
* INVALID for addresses not validated against the RPC
* VALID for addresses that validated fine

Just to give people a small tool at hands. Usually addresses are already
validated during account edit, so this script is mostly for those pools
that have not had that change yet and wish to notify their users.

Addresses #1177
[ADDED] Payout fail hint: Wallet covers balance?
Merge pull request #1275 from TheSerapher/issue-1177

Issue 1177
[FIX] RPC exception on empty address
[ADDED] Mark locked accounts during validation
[ADDED] User overview in admin dashboard

* Total users
* Locked users
* Admin users
* No Fees users

Thanks @daygle for the suggestion!

Fixes #1277 once merged
Merge pull request #1278 from TheSerapher/issue-1277

[ADDED] User overview in admin dashboard
Updated max lenght of username field in password-reset form

As the password reset form can also accept emails, increased the max-length size to 50 - so that we can accept long emails too.
Increased password-reset form username size to 100

Increased the accepted max-length to 100 as requested:  https://github.com/TheSerapher/php-mpos/pull/1279#issuecomment-31732351
Merge pull request #1279 from raistlinthewiz/next

Updated max lenght of username field in password-reset form
Fixed documentation typos.
Merge pull request #1284 from vekexasia/patch-1

Fixed documentation typos.
[CLEANUP] Registration page