major cleanup

cleaned <references> to proper format
split HTTPCache.ts into more files
cleaned xm module
* renamed xm.ObjectUtil to xm.object
* renamed xm.FileUtil to xm.file
* renamed xm.DateUtil to xm.date
* renamed xm.converString* to xm.parseString*
* dissolved xm/io folder to map folder
added xm helpers
* json-schema
* enum
added --cacheMode option to CLI
* applied --cacheMode to cli test
* fixes problem with updates to the fixed cache
tuned HTTPCache and timings
dropped unnecessary _info.json
updated cli help fixture
fixed some lint
made many small edits