adding support for most Sentinel methods

Merge branch 'patch-1' of https://github.com/stas-sultanov/StackExchange.Redis into stas-sultanov-patch-1

Conflicts:
	StackExchange.Redis/StackExchange/Redis/ConfigurationOptions.cs

Note: tweaked a bit

Spelling fix

RedisValue HasValue property

Add innerexception message in case of a fault 

for 'NOAUTH Authentication required.' recordconnection failure

Default connection timeout to 5 <s>milliseconds</s> seconds

Scripting now correctly returns the correct hash byte[] (half-width), and accepts hashes automatically as either byte[] or naked sha1 string

Fix compilation for MD/XS