Postgres column names are case sensitive (uppercase / lowercase)

Hi all,

I'm upgrading from exposed 0.12.1 to 0.17.7, and suddenly my tests are failing. This is because of the casing of the columns. I've reverted back to our old Exposed.

In our Exposed classes, our columns are mapped in upper case:

```
val G: Column =
integer("G")
```

but when executing the query, Exposed is doing an insert using a lower case `g`:

```
SQL: [INSERT INTO raw_data.raw ("g") VALUES (?)
```

Which results in an error:

```
Caused by: org.postgresql.util.PSQLException: ERROR: column "g" of relation "raw" does not exist
```

This doesn't happen for all our columns, we also have columns with spaces in it, which seem to be unaffected.