Merge branch 'master' of https://github.com/shiweichuan/StackExchange.Redis into shiweichuan-master (taken back to master - major merge pain)

Conflicts:
	StackExchange.Redis/StackExchange/Redis/RedisDatabase.cs

Issue #111: HashSet with RedisValue.EmptyString do not work as ""

A fix for https://github.com/StackExchange/StackExchange.Redis/issues/20

fix keyExpiry's DateTime convert to Utc

Named script parameters squashed

provide a way of overriding the task factory which se.redis will use #159

slave-of should help us out by a: not preserving a known-bad "master" value, and b: telling anyone listening about the pending change

Prevent EVAL to SCRIPT conversion if it is not supported 

Unhandled exception in callback when connection is disposed

Adding an environ var (SERedis_ClientCertStorageFlags) for configuring which cert store to check.

Added ability to write to a non-readonly slave

Azure stale connection detection

Fixed connect timeout handling in ConnectionMultiplexer.Connect

Update Basics.md typo

add TryParse() methods to Redis.Value for common conversion; exposing publicly functions already available internally

expose Prepend and Append methods on RedisKey, so we can avoid some string concats in common cases

add TryParse() methods to Redis.Value for common conversion; exposing publicly functions already available internally

Simple reorder of static field init order fixes this issue.