1. All services are disabled in testing now to prevent network accesses
2. Only services are enabled when needed to test something
3. Many changes throughout code to allow iD to run with services disabled
(e.g. check for osm service instead of assuming context.connection() will work)
4. Actually export the services so we can disable and enable them
(closes#2633)
* move osmChangeJXON from osm service to osmChangeset
* cleanup putChangeset for code clarity
* adjust params for callbacks (pass changeset around instead of changeset_id)
* add commit.reset() to reset changeset object after successful save
* improve checks for changeset tags (trim whitespace, etc)
