Add some more core defs to core-defs
Simplify: let keyword-invoke syntax be desugared at runtime

Instead of manually converting forms resembling (:kw target) to the
canonical (get target :kw) form, rely on the fact that keywords implement
IFn and can therefore be "invoked" at runtime without requiring any
special support by the compiler.
Simplify: temporarily remove dot (.) interop syntax desugaring

Eventually dot interop syntax will be reintroduced, and will compile to the
equivalent aget and aset special forms. However, for the initial version of
the compiler, aget and aset alone will suffice, and the nuances of dot syntax
can be temporarily ignored.
Analyzer and emitter support for aget and aset special forms