use separate script cache for ReferenceResolver

- ReferenceResolver fills cache in dependency-last order,
  via getScriptSnapshot
- type checker needs scripts in dependency-first order
- use separate cache, and fill language service host cache
  from resolution result (dependency-first)
tss.vim: prefix global python var with TSS_
add/fix types
rudimentary support for getScriptLexicalStructure
tss.vim: add TSSfiles - show project file list
tss.vim: add TSSbrowse - browse url for ES5 global property/method
fix lastError regexp
use inline dump to simplify tests
support partial updates; tests
add failure test to alert us when #13 is fixed, TS-side
support update without diagnostics (cf #13, #14)
add basic Makefile