added some unit tests for formatter
some initial work on multi level time axes
added actual .ts files and quicktest
fixed a few typos
working version
rearranged a bit
added a few more intervals
removed _interval from multiTimeAxis
added formatter per level
2-level labelings
Merged in master
fixed errors from merging in master
Merge branch 'master' into multi-time-axis
made enough space for major axis
now properly hides end tickLabels
also dynamically computes tickLength based on textHeight
removed formatters from constructor
fixed typo
removed the minorToMajor array confusion
made isEnoughSpace much faster
reorganized getTickValues to make it more clear
also reorganized _doRender to make it more clear
fixed a few minor bugs