Wrap-up
Removed timestep column.
Added the json files to ingest some of the snapshots.
Fix comment style
Change the format of user facing format of relation keys. This makes them consistent with MyriaL
Require postgres for profiling, rename opName -> opId in profiling schema, new data format for profiling data which we transform into after a query has finished and profiling data is flushed.
Fix comment
Correct error logging
rewrite getHistogram to support new data format
Rewrite queries to use trace id
Get range using api
Delete profiling data after transformation, fix queries
Fix getRange query
Implement profiling data api with new table format
Check whether step size is greater than 0
myria: turn on null analysis

This automatically identified a whole buncha bugs.
SQLiteAccessMethod: fix possible NPE
JsonQueryBaseBuilder: fix possible NPE

We are given children, which may be null, in which case we allocate
this.children. But then we still iterate over children instead of
this.children, which could have caused null pointer exception.
DatasetResource: fix possible NPE
Server: fix possible NPE

We allow profilingMode to be null, then cast it to a boolean. Better work around that!