ENH: stats.dlaplace.rvs improvements
ENH: stats.dlaplace.rvs improvements

This commit incorporates the following recommendations:
1) Add references in the comments
2) Use np.expm1 to improve accuracy

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