* Add Int4 and Int8 integer expression to distinguish int4range and int8range types
* Add range functions to range expressions to avoid go template appearing in sql
* Compact range integration tests and add range update tests
plus and minus infinity keyword tests implemented
range table tests added
skip cockroach db added
select test case added for range fields
generator modified to generate correct types
generator tests modified to include sample range table
model and template generators modified to support range fields
returning the T in UPPER and LOWER functions
raw ranges implemented
bounds set as optional
dep modified
dependencies modified and issue fixed
range expression with templates implemented
rangeExpression change to make it more type safe
third parameter of constructor function fixed
literals removed, functions added
tests modified
constructor functions used for creating range expressions
NumRange converted to a constructor function from literal
range_lower and range_upper renamed to lower_bound and upper_bound
range literal removed
PlusInfinity and MinusInfinity implemented
int4 and int8 castings added
issues fixed and tests checked
number, ts, tstz literal and cast implemented
date range literal expression modified and raw function used
parent type converted from RangeExpression to Expression
range type implemented for postgres
range column type, function and literal expression implemented
CONTAINS and OVERLAP operations added for range expressions
range expressions implemented
Move typeStack to ScanContext, so it is shared between rows.Scan calls.
Use string.Builder for string concatenations.
Simplify value assign logic.
Move convert value to the last assign step (needs for type conversions are rare).
