Cleanup SerDeUtils
Update docs for color functions
Provide locale via X-Presto-Language header

The expected format is as defined by IETF BCP 47 (http://tools.ietf.org/html/bcp47)
Run tests with fractional hour timezone offset
Fix expected timestamp in test
Make formatTimestamp methods private
Move exception propagation to utility method
Handle broken timestamp ObjectInspectors
Add Hive plugin for CDH 5
Allow evaluateConstantExpression to return non-literal constant expressions

Literals for types other than the basic ones and certain values for double (NaN, infinity)
are represented via function calls to "magic" constructors. Currently, queries such as these
don't work:

VALUES (now())

VALUES (0.0/0.0)
Fix planning issue with date/time constructs in VALUES

Planning VALUES requires optimizing and constant-folding expressions.
The interpreter/optimizer can only deal with a subset of AST node types
(e.g., CurrentTime is not supported).

To work around this until the new expression tree is implemented, canonicalize
expressions before feeding them to the optimizer/interpreter.
Add support for plugin provided operators
Rename tests to match class names
Shorten TimeZoneKey method names
Require functions and operators to explicitly declare SqlTypes