Redesign evaluation of dependent properties in AstList and AstOption.
Minor optimizations of DataProxy for AstOption.
Fix AstOption construction.
Generic construction of list and option ast.
Merge remote-tracking branch 'origin/DependentProperties' into hardcase_work

Conflicts:
	Nitra/Nitra.Runtime/Declarations/AstList.n
Fix build.
Change “declare” syntax to “map syntax”.
Work on keyword completion.
Fix a bug.
Merge remote-tracking branch 'origin/hardcase_work' into DependentProperties

Conflicts:
	Nitra/Nitra.Runtime/Nitra.Runtime.nproj