ARROW-1595: [Python] Fix package dependency resolution issue causing broken builds
ARROW-1595: [Python] Fix package dependency resolution issue causing broken builds

One of the dependencies installed in the docs requirements is causing NumPy to get downgraded by the SAT solver, and this is then causing an ABI conflict with the pyarrow build (which was built with a different version of NumPy). This installs everything in one `conda install` call

Author: Wes McKinney <wes.mckinney@twosigma.com>

Closes #1123 from wesm/ARROW-1595 and squashes the following commits:

60b05ad5 [Wes McKinney] Install conda dependencies all at once, pin NumPy version

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