Refactoring and clean-up of core classes and interfaces

Conflicts:
	src/ch/uzh/ifi/attempto/acewiki/aceowl/ACESentence.java
	src/ch/uzh/ifi/attempto/acewiki/core/AbstractSentence.java
	src/ch/uzh/ifi/attempto/acewiki/core/MonolingualSentence.java
	src/ch/uzh/ifi/attempto/acewiki/core/MultilingualSentence.java
	src/ch/uzh/ifi/attempto/acewiki/core/Sentence.java
	src/ch/uzh/ifi/attempto/acewiki/gfservice/GFDeclaration.java
	src/ch/uzh/ifi/attempto/acewiki/gui/SentenceComponent.java
	src/ch/uzh/ifi/attempto/acewiki/gui/TextRow.java
	src/ch/uzh/ifi/attempto/acewiki/gui/TranslationsPage.java
Add missing libraries; documentation
Adopt some (mostly minor) changes from GF branch
Merge remote-tracking branch 'origin/master' into gfservice

Conflicts:
	.classpath
	build.xml
	src/ch/uzh/ifi/attempto/acewiki/core/MultilingualSentence.java
	src/ch/uzh/ifi/attempto/acewiki/core/Sentence.java
	src/ch/uzh/ifi/attempto/acewiki/gf/GFDeclaration.java
	src/ch/uzh/ifi/attempto/base/MultiTextContainer.java
	src/ch/uzh/ifi/attempto/echocomp/GeneralWindow.java