Update for 0.6.4.4 beta 2

Implements a new retarget strategy at block #87948 supporting combined average windows of 126 and 504 blocks with .25 damping.
Changed CAlert key
Activated CAlert
Activated CAlert in Qt GUI
Time Warp Limitation
Time Warp Limitation (cont'd)
Version Update to 0.6.4.4
Version Update to 0.6.4.4 in Qt GUI
Sendalert Added

The code to send network alerts. Imported from PPC/XPM.
Testnet Difficulty and Activation Updated
Time Warp: New Future and Past Limits
Separate Alert Keys for Livenet and Testnet
Protocol Version Update
BitcoinMiner -> FeathercoinMiner Name Update
BitcoinMiner -> FeathercoinMiner Name Update
Fix for URI Handling
A Cumulative Update
Daemon's Start-Up Message Removed
Merge pull request #3 from ghostlander/0.6.4.4

v0.6.4.4 Branch Merge