Finding areas that are untested and need love (#4131)

* Makes InstallationRouter like others

* Adds testing for Range file requests

- Fixes issue with small requests (0-2)

* Revert "Makes InstallationRouter like others"

This reverts commit e2d2a16ebf2757db6138c7b5b33c97c56c69ead6.

* Better handling of errors in FilesRouter

* Fix incorrectness in range requests

* Better/simpler logic

* Only on mongo at it requires Gridstore

* Open file streaming to all adapters supporting it

* Improves coverage of parsers

* Ensures depreciation warning is effective

* Removes unused function

* de-duplicate logic

* Removes necessity of overriding req.params.className on subclasses routers

* Use babel-preset-env to ensure min-version compatible code

* removes dead code

* Leverage indexes in order to infer which field is duplicated upon signup

- A note mentioned that it would be possible to leverage using the indexes on username/email to infer which is duplicated

* Small nit

* Better template to match column name

* Restores original implementation for safety

* nits

src/triggers.js

@@ -54,25 +54,11 @@ export function removeFunction(functionName, applicationId) {
   delete _triggerStore[applicationId].Functions[functionName]
 }
 
-export function removeJob(jobName, applicationId) {
-  applicationId = applicationId || Parse.applicationId;
-  delete _triggerStore[applicationId].Jobs[jobName]
-}
-
 export function removeTrigger(type, className, applicationId) {
   applicationId = applicationId || Parse.applicationId;
   delete _triggerStore[applicationId].Triggers[type][className]
 }
 
-export function _unregister(appId,category,className,type) {
-  if (type) {
-    removeTrigger(className,type,appId);
-    delete _triggerStore[appId][category][className][type];
-  } else {
-    delete _triggerStore[appId][category][className];
-  }
-}
-
 export function _unregisterAll() {
   Object.keys(_triggerStore).forEach(appId => delete _triggerStore[appId]);
 }