Protocol, error handling, other improvements

[gbakeman]

Notable changes

• Fixes UI becoming frozen when connection is suddenly disconnected
• Communication timeout is now 5 seconds making broken connections detectable faster than before (timeout was about 30 seconds.) However, communication is still synchronous with the UI so WinNUT will appear to hang during any socket operations (connect, read or write).
• Connection error handling is more consistent
• Fixes bug where data was not available for the time it takes till the next poll.

Outline

• Removed redundant checks during queries
• Added comments and documentation

Common_Enums:

• Removed "EMPTY" NUTResponse; EndOfStreamException thrown instead.

Common_Classes:

• Adding String array to Transaction class to store split responses so split operation doesn't need to be repeated for later processing.
• Removed extra NutError constructor

Nut_Socket:

• Specified 5 second timeout for socket communication (outside of initial connection) so broken connections are handled faster
• Specified protocol character encoding for the sake of exactness (doesn't necessarily change functionality)
• Take entire string returned in VER query, rather than looking for server semver.
• Slightly adjust order of operations in Connect subroutine
• Adding OnSocketBroken subroutine to handle errors during Query_Data
• Catch exceptions when reading and writing to the socket so the object can reset its state and disconnect
• Remove unnecessary operations on response string
• Opportunistically throw exceptions when necessary during response parsing

UPS_Device:

• Start Update_Data timer later on in connection sequence, and retrieve a copy of the data right away.
• Enhanced parameter checking in GetUPSVar
• Simplified response verification
• Combined exception handling and record the last exception
• For Loop is only continued under specific circumstances now
• Better error logging towards end of GetUPSVar

Closes #223