Minor improvements to readme
Minor improvements to readme

* Use Pip instead of EasyInstall.
* Add note on Vagrant / emulator conflict.
* Add note on code, commit, and doc conventions.
* Fix some capitalizations.

Change-Id: I0d5e7e39f057635758fbfc601aa20aed8b79e1c5

reproio/apps-android-wikipedia,Wikinaut/wikipedia-app,carloshwa/apps-android-wikipedia,carloshwa/apps-android-wikipedia,dbrant/apps-android-wikipedia,anirudh24seven/apps-android-wikipedia,parvez3019/apps-android-wikipedia,reproio/apps-android-wikipedia,dbrant/apps-android-wikipedia,reproio/apps-android-wikipedia,reproio/apps-android-wikipedia,Wikinaut/wikipedia-app,reproio/apps-android-wikipedia,wikimedia/apps-android-wikipedia,Wikinaut/wikipedia-app,Duct-and-rice/KrswtkhrWiki4Android,carloshwa/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,parvez3019/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,wikimedia/apps-android-wikipedia,carloshwa/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,parvez3019/apps-android-wikipedia,wikimedia/apps-android-wikipedia,Wikinaut/wikipedia-app,SAGROUP2/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,wikimedia/apps-android-wikipedia,anirudh24seven/apps-android-wikipedia,parvez3019/apps-android-wikipedia,parvez3019/apps-android-wikipedia,Wikinaut/wikipedia-app,anirudh24seven/apps-android-wikipedia,dbrant/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,carloshwa/apps-android-wikipedia,dbrant/apps-android-wikipedia,anirudh24seven/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,anirudh24seven/apps-android-wikipedia,dbrant/apps-android-wikipedia