ARROW-351: Time type has no unit
ARROW-351: Time type has no unit

Author: Julien Le Dem <julien@dremio.com>

Closes #328 from julienledem/arrow_351 and squashes the following commits:

2497ee3 [Julien Le Dem] ARROW-351: Time type has no unit

yufeldman/arrow,renesugar/arrow,yufeldman/arrow,siddharthteotia/arrow,laurentgo/arrow,itaiin/arrow,cpcloud/arrow,laurentgo/arrow,dremio/arrow,jeffknupp/arrow,NonVolatileComputing/arrow,apache/arrow,majetideepak/arrow,renesugar/arrow,kou/arrow,itaiin/arrow,kou/arrow,siddharthteotia/arrow,xhochy/arrow,icexelloss/arrow,apache/arrow,pcmoritz/arrow,laurentgo/arrow,wesm/arrow,itaiin/arrow,renesugar/arrow,apache/arrow,apache/arrow,jeffknupp/arrow,laurentgo/arrow,StevenMPhillips/arrow,itaiin/arrow,tebeka/arrow,siddharthteotia/arrow,julienledem/arrow,cpcloud/arrow,renesugar/arrow,kou/arrow,laurentgo/arrow,itaiin/arrow,StevenMPhillips/arrow,NonVolatileComputing/arrow,apache/arrow,julienledem/arrow,cpcloud/arrow,itaiin/arrow,jeffknupp/arrow,tebeka/arrow,yufeldman/arrow,cpcloud/arrow,julienledem/arrow,xhochy/arrow,dremio/arrow,pcmoritz/arrow,tebeka/arrow,majetideepak/arrow,NonVolatileComputing/arrow,majetideepak/arrow,wesm/arrow,dremio/arrow,kou/arrow,StevenMPhillips/arrow,cpcloud/arrow,NonVolatileComputing/arrow,wesm/arrow,StevenMPhillips/arrow,tebeka/arrow,renesugar/arrow,kou/arrow,icexelloss/arrow,xhochy/arrow,xhochy/arrow,julienledem/arrow,dremio/arrow,laurentgo/arrow,yufeldman/arrow,TheNeuralBit/arrow,majetideepak/arrow,renesugar/arrow,apache/arrow,renesugar/arrow,NonVolatileComputing/arrow,yufeldman/arrow,itaiin/arrow,laurentgo/arrow,dremio/arrow,siddharthteotia/arrow,laurentgo/arrow,wagavulin/arrow,julienledem/arrow,tebeka/arrow,StevenMPhillips/arrow,kou/arrow,majetideepak/arrow,icexelloss/arrow,wesm/arrow,icexelloss/arrow,cpcloud/arrow,apache/arrow,itaiin/arrow,NonVolatileComputing/arrow,dremio/arrow,NonVolatileComputing/arrow,apache/arrow,julienledem/arrow,icexelloss/arrow,apache/arrow,StevenMPhillips/arrow,jeffknupp/arrow,TheNeuralBit/arrow,xhochy/arrow,pcmoritz/arrow,pcmoritz/arrow,majetideepak/arrow,kou/arrow,kou/arrow,majetideepak/arrow,cpcloud/arrow,pcmoritz/arrow,majetideepak/arrow,laurentgo/arrow,TheNeuralBit/arrow,wagavulin/arrow,renesugar/arrow,wagavulin/arrow,laurentgo/arrow,cpcloud/arrow,wagavulin/arrow,itaiin/arrow,wesm/arrow,majetideepak/arrow,tebeka/arrow,siddharthteotia/arrow,wesm/arrow,tebeka/arrow,kou/arrow,dremio/arrow,wagavulin/arrow,icexelloss/arrow,icexelloss/arrow,StevenMPhillips/arrow,wesm/arrow,itaiin/arrow,majetideepak/arrow,renesugar/arrow,tebeka/arrow,wagavulin/arrow,renesugar/arrow,julienledem/arrow,majetideepak/arrow,itaiin/arrow,pcmoritz/arrow,xhochy/arrow,jeffknupp/arrow,jeffknupp/arrow,yufeldman/arrow,julienledem/arrow,laurentgo/arrow,kou/arrow,renesugar/arrow,icexelloss/arrow,pcmoritz/arrow,NonVolatileComputing/arrow,renesugar/arrow,icexelloss/arrow,jeffknupp/arrow,apache/arrow,cpcloud/arrow,tebeka/arrow,NonVolatileComputing/arrow,wesm/arrow,laurentgo/arrow,StevenMPhillips/arrow,kou/arrow,majetideepak/arrow,siddharthteotia/arrow,majetideepak/arrow,wagavulin/arrow,itaiin/arrow,TheNeuralBit/arrow,julienledem/arrow,pcmoritz/arrow,dremio/arrow,laurentgo/arrow,renesugar/arrow,pcmoritz/arrow,itaiin/arrow,apache/arrow,icexelloss/arrow,renesugar/arrow,jeffknupp/arrow,wesm/arrow,cpcloud/arrow,apache/arrow,laurentgo/arrow,majetideepak/arrow,siddharthteotia/arrow,xhochy/arrow,kou/arrow,julienledem/arrow,cpcloud/arrow,pcmoritz/arrow,yufeldman/arrow,icexelloss/arrow,jeffknupp/arrow,wesm/arrow,TheNeuralBit/arrow,pcmoritz/arrow,wagavulin/arrow,cpcloud/arrow,wagavulin/arrow,wagavulin/arrow,cpcloud/arrow,tebeka/arrow,dremio/arrow,xhochy/arrow,majetideepak/arrow,xhochy/arrow,yufeldman/arrow,TheNeuralBit/arrow,apache/arrow,yufeldman/arrow,siddharthteotia/arrow,jeffknupp/arrow,siddharthteotia/arrow,itaiin/arrow,pcmoritz/arrow,jeffknupp/arrow,kou/arrow,pcmoritz/arrow,siddharthteotia/arrow,icexelloss/arrow,xhochy/arrow,pcmoritz/arrow,NonVolatileComputing/arrow,apache/arrow,kou/arrow,dremio/arrow,wesm/arrow,icexelloss/arrow,dremio/arrow,siddharthteotia/arrow,xhochy/arrow,laurentgo/arrow,icexelloss/arrow,yufeldman/arrow,wesm/arrow,NonVolatileComputing/arrow,itaiin/arrow,wagavulin/arrow,StevenMPhillips/arrow,xhochy/arrow,xhochy/arrow,yufeldman/arrow,renesugar/arrow,wesm/arrow,xhochy/arrow,pcmoritz/arrow,wesm/arrow,StevenMPhillips/arrow,cpcloud/arrow,wagavulin/arrow,xhochy/arrow