mailer: simplify & adapt wording

output => stringer
no more sendError, we will see later for error reporting
refucktored datastringer.js
ongoing refucktoring: add crime stringer and remove data source and output for police UK
MASSIVE FILE EPURATION
Crimestringer: add some todo.
Datastringer: fix typos
Mailer: fix typo
clean-up
+local-police-stringer.js
Remove old things related to datasource-locale-police-uk

MAN DOES THAT FEEL GOOD
+asset_manager.js
local police stringer: use asset manager
crime-stringer: comments
dependencies: remove jsonfn
crime-stringer: store last udpate date for reference, as an asset
app.js: rewrite the config file in place
factorize the config read and write functions
Merge branch 'refucktoring'