Began to implement user accounts using the database

I'm mostly just testing the waters at this stage, and i've left some debug
code in. There's no way to unload, delete, etc. the accounts, but that
comes later.
Merge branch 'master' into database (read more)

Conflicts:
	todo.txt (kept)

Just merging the editor's deletion into this branch, nothing else major.
Switched to using a wildcard symbol
BUGFIX: Signal when a duplicate account is being loaded

If a duplicate account is being created or loaded then the functions
return -1. The higher code can take it from there.
Implemented saving of user accounts (read more)

To modify an existing user account, change the in memory copy and then
call the function SaveUserAccount(uid), where uid is the index of the
modified account. If the save function is not called immediately, then the
behaviour of the server is undefined.
Added Unloading and Deletion of user accounts
Minor tweaks, prepping for a merge
Merge branch 'database' (read more)

* Implemented user accounts.
* Other minor tweaks

I think the general "clientIndex" variable needs to be changed to
"accountIndex", since this will allow for much easier authentication.