Completion migration

AnonFunctionProposal

✅ IJ
✅ EC

ArgumentProposalComparator

✅ Common

BasicCompletionProposal

✅ IJ
✅ EC

ControlStructureCompletionProposal

✅ IJ
✅ EC

TODO: the selection is duplicated in ControlStructureCompletionProposal and ideaCompletionManager

FunctionCompletionProposal

✅ IJ
✅ EC

InvocationCompletionProposal

✅ IJ
✅ EC

KeywordCompletionProposal

✅ IJ
✅ EC

MemberNameCompletions

✅ IJ
✅ EC

ModuleCompletions

✅ IJ
❌ EC

PackageCompletions

✅ IJ
❌ EC (don't forget to replace ModuleImportUtil with an object that extends AbstractModuleImportUtil, and remove ModuleNode and ModuleVersionNode from ceylon-ide-eclipse)

ParametersCompletionProposal

✅ IJ
❌ EC

TODO linked mode (there's also code duplicated from InvocationProposal: nested classes, linked mode etc)

ProposalComparator

✅ Common

RefinementCompletionProposal

✅ IJ
✅ EC

TypeArgumentListCompletions

✅ IJ
✅ EC