…ncremental builds

…on to set Program in state to undefined for storing.

This helps in storing the semantic diagnostics

… of incremental build

This ensures that after `tsbuild` after incremental build of `tsbuild -w` doesnt result in unnecessary rebuilds

…oject reference with prepend since it cant tell changes in js/map files

…dling

These will fail since its still TODO

…state

This helps us revert to state where we pretend as if emit is not done (since we do not do emit if there are errors)