Bug(regression): Relation attrIndex keys are in lower case but lookup is not

[trakhimenok]

Started to get this error after upgrading from v0.0.1 to v0.1.0:

"attribute not defined"

I have this table definition:

CREATE TABLE DalgoE2E_E2ETest1 (ID1 VARCHAR(10) PRIMARY KEY, StringProp TEXT, IntegerProp INT);

And am trying to query data as:

SELECT StringProp, IntegerProp FROM DalgoE2E_E2ETest1

Column names comes to the func (r *Relation) Attribute(name string) (int, Attribute, error) in original CamelCase but are in lower case in Relation.attrIndex.

I believe this line should bring the name to lowercase like:

index, ok := r.attrIndex[strings.ToLower(name)]

[proullon]

Issue is still present, cf failing test in #fix/86