don't force to lowercase

@bmyerz: Will it break anything for you if we stop forcing field names to lowercase? This change would be accompanied by changes in `igor_common` to not force parsed things to lowercase. The issue I'm seeing is that this behavior is causing Igor to think it needs to create a new column because it doesn't recognize the different-case name, and then it errors creating the "new" column in Sequel:

```
/sampa/share/linuxbrew/lib/ruby/gems/gems/sqlite3-1.3.8/lib/sqlite3/database.rb:91:in `initialize': SQLite3::SQLException: duplicate column name: sizea (Sequel::DatabaseError)
```