Modify ERXExistsQualifier to fix a problem with it constructing bad SQL if the baseKeyPath actually contained a keyPath instead of a simple key. Hackish fix created by making the constructor recursive for the keyPath, in-effect creating nested ERXExistsQualifier sub qualifiers.
StringUtils.replace

Using StringUtils.replace() instead of ERX version of it since it is deprecated.

Signed-off-by: Aaron Rosenzweig <aaron@chatnbike.com>