Adds Callfunc Completion and Validation

[markwpearce]

Gives callFunc a whole lotta love!

• Fixes an issue with completions on @. where ALL possible callfuncs would appear. This was a result of the parser having an exception on incomplete @. invocations
• Adds function documentation to hovers on @. callfunc invocations
• Stores all resolved types associated with callfuncs for a component in a symbolTable that is used a sibiling table when the callfunc is used in another scope
• Return type of Callfunc and @. invocations are used to set types in assignments
• Validates arg counts and type mismatches for callfunc and @.

While I was it, I also added validation and return typing for <component>.createChild()

Additional validation enhancements:

• if a type depends on another type (eg, has a member of another type), and that member type changes, then all segments/ASTNodes that reference the wider type are also re-validated. This means that the type-safety flows down and things get appropriately re-validated when there are changes.
• Better handling of typecast statements when setting up file segments for revalidation
• Better handling of when component types change, and re-validation because of that.

TODO:

• Make validation updates work better. Currently, you need to edit an XML file of the component for things to revalidate if the exported function type changes
• Deal with how adding sibling tables messes up other validations. Like if the resolved version stay around when they actually should be unresolved
• Do not have validation errors if the component type is the generic roSGNode

To be honest, I think that if we properly re-build the Component type when a member file changes, that would fix both problems.

Also fixes #1309

[markwpearce]

@TwitchBronBron This is ready for review

[TwitchBronBron]

Overall, it seems to be working fairly well. I've added a few comments for some bugs I found. Looking forward to testing it again!