Added documentation.
Used initializer lists instead of old (inferior) initialization
technique.
Read/write support for GlossItems with baseline writing systems
different from that of the text.
I weeded out some DatabaseAdapter members (and getters and setters) that
should not have been used. This ended up breaking a couple of things,
which are now marked with TODO tags.
Modified the configuration.xml read functions so that you can specify
different interlinear displays for words with different baseline writing
systems.