TST: Added new tests and modified old ones for from_rotvec
TST: Added new tests and modified old ones for from_rotvec

Added a test case for small angles. Modified previous tests to use
as_quaternion function instead of accessing ._quat directly

andyfaff/scipy,jor-/scipy,zerothi/scipy,aeklant/scipy,Stefan-Endres/scipy,matthew-brett/scipy,grlee77/scipy,ilayn/scipy,WarrenWeckesser/scipy,jor-/scipy,zerothi/scipy,mdhaber/scipy,pizzathief/scipy,arokem/scipy,endolith/scipy,mdhaber/scipy,Stefan-Endres/scipy,pizzathief/scipy,perimosocordiae/scipy,gfyoung/scipy,aeklant/scipy,scipy/scipy,WarrenWeckesser/scipy,WarrenWeckesser/scipy,e-q/scipy,WarrenWeckesser/scipy,zerothi/scipy,gfyoung/scipy,scipy/scipy,scipy/scipy,rgommers/scipy,Eric89GXL/scipy,Eric89GXL/scipy,aarchiba/scipy,gfyoung/scipy,lhilt/scipy,endolith/scipy,grlee77/scipy,jamestwebber/scipy,anntzer/scipy,Stefan-Endres/scipy,Eric89GXL/scipy,matthew-brett/scipy,person142/scipy,aarchiba/scipy,scipy/scipy,perimosocordiae/scipy,gertingold/scipy,Stefan-Endres/scipy,pizzathief/scipy,jor-/scipy,gertingold/scipy,rgommers/scipy,perimosocordiae/scipy,andyfaff/scipy,mdhaber/scipy,matthew-brett/scipy,aeklant/scipy,andyfaff/scipy,nmayorov/scipy,Eric89GXL/scipy,tylerjereddy/scipy,nmayorov/scipy,vigna/scipy,ilayn/scipy,nmayorov/scipy,jamestwebber/scipy,nmayorov/scipy,anntzer/scipy,gertingold/scipy,ilayn/scipy,tylerjereddy/scipy,jamestwebber/scipy,arokem/scipy,grlee77/scipy,person142/scipy,e-q/scipy,Eric89GXL/scipy,person142/scipy,andyfaff/scipy,mdhaber/scipy,ilayn/scipy,lhilt/scipy,lhilt/scipy,grlee77/scipy,endolith/scipy,anntzer/scipy,lhilt/scipy,aeklant/scipy,perimosocordiae/scipy,WarrenWeckesser/scipy,gfyoung/scipy,e-q/scipy,Stefan-Endres/scipy,Stefan-Endres/scipy,gertingold/scipy,endolith/scipy,mdhaber/scipy,zerothi/scipy,arokem/scipy,matthew-brett/scipy,arokem/scipy,anntzer/scipy,tylerjereddy/scipy,e-q/scipy,grlee77/scipy,nmayorov/scipy,scipy/scipy,andyfaff/scipy,rgommers/scipy,jor-/scipy,arokem/scipy,perimosocordiae/scipy,scipy/scipy,ilayn/scipy,zerothi/scipy,anntzer/scipy,perimosocordiae/scipy,pizzathief/scipy,aeklant/scipy,zerothi/scipy,rgommers/scipy,vigna/scipy,pizzathief/scipy,rgommers/scipy,matthew-brett/scipy,jamestwebber/scipy,WarrenWeckesser/scipy,jor-/scipy,gfyoung/scipy,Eric89GXL/scipy,vigna/scipy,e-q/scipy,aarchiba/scipy,tylerjereddy/scipy,vigna/scipy,mdhaber/scipy,aarchiba/scipy,vigna/scipy,endolith/scipy,tylerjereddy/scipy,anntzer/scipy,person142/scipy,person142/scipy,ilayn/scipy,lhilt/scipy,aarchiba/scipy,endolith/scipy,gertingold/scipy,andyfaff/scipy,jamestwebber/scipy