docs(ember): Add note for tying karma start to App.initialize
docs(ember): Add note for tying karma start to App.initialize

Tests against an ember application should not start until the
App has completed initializing.  The note and suggested
bootstrap method demonstrate how to deactivate karma autostart
and how to explicitly start karma at the appropirate time.

Closes #1012

patrickporto/karma,marthinus-engelbrecht/karma,rgaskill/karma,stevemao/karma,Dignifiedquire/karma,vtsvang/karma,karma-runner/karma,bitwiseman/karma,astorije/karma,powerkid/karma,buley/karma,IsaacChapman/karma,harme199497/karma,youprofit/karma,astorije/karma,jsdir/karma,Klaudit/karma,clbond/karma,buley/karma,pedrosnk/karma,IveWong/karma,shirish87/karma,Dignifiedquire/karma,jamestalmage/karma,gayancliyanage/karma,ernsheong/karma,hitesh97/karma,johnjbarton/karma,karma-runner/karma,dmitriiabramov/karma,yandex-lego/karma,ijobling/karma,jsdir/karma,stevemao/karma,nmalaguti/karma,codedogfish/karma,tomkuk/karma,KrekkieD/karma,IsaacChapman/karma,wesleycho/karma,clbond/karma,IveWong/karma,mprobst/karma,youprofit/karma,panrafal/karma,rhlass/karma,IsaacChapman/karma,pmq20/karma,growlybear/karma,jeffjewiss/karma,youprofit/karma,behzad88/karma,xiaoking/karma,adamnation/karma,pedrotcaraujo/karma,unional/karma,aiboy/karma,aiboy/karma,astorije/karma,marthinus-engelbrecht/karma,aiboy/karma,pmq20/karma,growlybear/karma,patrickporto/karma,ernsheong/karma,gayancliyanage/karma,lencioni/karma,codedogfish/karma,kahwee/karma,brianmhunt/karma,lencioni/karma,unional/karma,powerkid/karma,yandex-lego/karma,Klaudit/karma,marthinus-engelbrecht/karma,marthinus-engelbrecht/karma,Klaudit/karma,Klaudit/karma,johnjbarton/karma,chrisirhc/karma,timebackzhou/karma,stevemao/karma,clbond/karma,Sanjo/karma,kahwee/karma,IveWong/karma,jjoos/karma,skycocker/karma,tomkuk/karma,timebackzhou/karma,codedogfish/karma,vojtajina/karma,johnjbarton/karma,ijobling/karma,karma-runner/karma,vtsvang/karma,xiaoking/karma,aiboy/karma,pmq20/karma,rgaskill/karma,panrafal/karma,simudream/karma,hitesh97/karma,bitwiseman/karma,jjoos/karma,pedrosnk/karma,maksimr/karma,nmalaguti/karma,rhlass/karma,codedogfish/karma,jamestalmage/karma,shirish87/karma,wesleycho/karma,jsdir/karma,Dignifiedquire/karma,xiaoking/karma,maksimr/karma,gayancliyanage/karma,karma-runner/karma,wesleycho/karma,clbond/karma,ijobling/karma,KrekkieD/karma,jjoos/karma,rhlass/karma,skycocker/karma,chrisirhc/karma,vojtajina/karma,jjoos/karma,tomkuk/karma,IsaacChapman/karma,timebackzhou/karma,brianmhunt/karma,astorije/karma,buley/karma,david-garcia-nete/karma,skycocker/karma,brianmhunt/karma,kahwee/karma,hitesh97/karma,growlybear/karma,timebackzhou/karma,pedrotcaraujo/karma,jamestalmage/karma,vtsvang/karma,adamnation/karma,chrisirhc/karma,patrickporto/karma,pedrotcaraujo/karma,dmitriiabramov/karma,unional/karma,nmalaguti/karma,maksimr/karma,pedrosnk/karma,harme199497/karma,SamuelMarks/karma,harme199497/karma,bitwiseman/karma,jeffjewiss/karma,rgaskill/karma,simudream/karma,panrafal/karma,chrisirhc/karma,brianmhunt/karma,ernsheong/karma,oyiptong/karma,jamestalmage/karma,vtsvang/karma,buley/karma,wesleycho/karma,dmitriiabramov/karma,stevemao/karma,Sanjo/karma,KrekkieD/karma,hitesh97/karma,youprofit/karma,SamuelMarks/karma,oyiptong/karma,patrickporto/karma,johnjbarton/karma,behzad88/karma,rhlass/karma,Sanjo/karma,vojtajina/karma,simudream/karma,harme199497/karma,simudream/karma,mprobst/karma,SamuelMarks/karma,pmq20/karma,david-garcia-nete/karma,Sanjo/karma,powerkid/karma,tomkuk/karma,kahwee/karma,xiaoking/karma,nmalaguti/karma,adamnation/karma,KrekkieD/karma,pedrotcaraujo/karma,shirish87/karma,IveWong/karma,oyiptong/karma,jeffjewiss/karma,gayancliyanage/karma,lencioni/karma,yandex-lego/karma,unional/karma,oyiptong/karma,mprobst/karma,skycocker/karma,david-garcia-nete/karma,powerkid/karma,Dignifiedquire/karma,behzad88/karma