Great performance increase on transaction queries

This will address an issue with database including a lot of
transactions. No more nested queries that put unwanted strain on a DB.

Address #536
Fixing WHERE clause for getBalance call

Addresses #536
Refactored admin transactions

* Properly generate the bind_params statement
* Extended from Base Class
* Added methods to Base Class

Addresses #536
Refactored getTransactions, unified admin/user view

* Removed getAllTransactions method
* Unified getTransactions for users and admins
* Added filter abilities to user transaction view

This should speed up things a fair bit for transaction heavy pools.

Addresses #536
Adding archiving flag for transactions

* Added new column to transactions table (`007_transactions.sql`)
* Added setArchived method to mark old transactions as archived
* Honor archived flag in getBalance and getLockedBalance

This will further address and fix #536 once merged.
properly display auto-confirmed tx
adding index to archived column
Merge pull request #556 from TheSerapher/issue-536

Issue 536