more core stuff
copied SDF3 versions from TS
improved formulas from TS
syntax for formulas and propositions
adopted analysis for syntactic changes, normalization of formulas
cleanup and fixed imports
fix import
reduced syntax to core
more propositions, or as an alternative to else
all the core stuff
Merge branch 'master' into core-syntax

Conflicts:
	org.metaborg.meta.lang.nabl/editor/NameBindingLanguage-Menus.esv
	org.metaborg.meta.lang.nabl/syntax/NameBindingLanguage.generated.pp
	org.metaborg.meta.lang.nabl/syntax/NameBindingLanguage.sdf3
	org.metaborg.meta.lang.nabl/syntax/common/Identifiers.sdf
	org.metaborg.meta.lang.nabl/syntax/common/Identifiers.sdf3
	org.metaborg.meta.lang.nabl/syntax/core/Modules.sdf
	org.metaborg.meta.lang.nabl/syntax/core/Modules.sdf3
	org.metaborg.meta.lang.nabl/syntax/terms/Vars.sdf
	org.metaborg.meta.lang.nabl/syntax/terms/Vars.sdf3
	org.metaborg.meta.lang.nabl/trans/analysis/names.nab
	org.metaborg.meta.lang.nabl/trans/generation/util.str
	org.metaborg.meta.lang.nabl/trans/names.nab
	org.metaborg.meta.lang.nabl/trans/names2.nab
fixed merge
generated files
only 3 formula combinators
simplified scope rule, should also fix a bug where empty rules were
generated
drop messages from formulas
desugaring and normalisation
factored out namespaces and properties section handling
got def sites, prop sites and scoping sites working with new formulas
propositions and formulas working