Added alignment parameters to aggregators

This pull request contains changes which I did to fix the issue https://github.com/kairosdb/kairosdb-client/issues/18 (which I submitted): it brings to kairosdb client ability to set parameters "align sampling" and "align start time" on aggregators - these parameters were introduced in KairosDB 0.9.4.
Should you split this somehow or convert to something else than boolean? It's hard to remember what withAlignment(true, true) really means compared to withStartTimeAlignment(true) and withSamplingAlignment(true) (fell free to use better methods names than suggested).