add default domain to time scale
simplified ticklevel logic
fix bug in getIntervalLength when scale's domain got very small
fix tslint
fix typo
Merge branch 'master' into 773-stack-trace
consolidate variables
Merge branch 'master' into 773-stack-trace

Conflicts:
	src/components/timeAxis.ts
Merge pull request #814 from palantir/773-stack-trace

Some time axis/scale clarifications