Convert username and password to member variables
Get the class name dynamically
Breakout the weather info into its own function
Updated the username and password parameters to use constants if not provided to the constructor.
Merge pull request #25 from chawkinsuf/master

Small improvements
Force TLSv1, as the Nest servers stopped allowing SSLv2 and even SSLv3.
Fixes #27
Added battery_level in device infos; thanks to Alan OConnor
Support for Nest Protect; getDeviceInfo() only for now, in addition to listing available Nest Protect devices in getLocationInfo()
Ensure cookie and cache files are secure (not group or world readable).
Fixes #29
Fixed typo in function signature. Fixes #30