various fixing from following the codelab step by step on Linux
updating instructions to match the changes in previous steps
updating the generator version to the latest tested with this codelab
Codelab: Pearl's updates to Ahmad's updates

Changelog:
- 2nd sweep for 0.9.0-1 breaking changes
- Swapped Step 9 and Step 10
- Cleaned up some screenshots for clarity
removing un-necessary line
Merge branch 'codelab-fixes-pearl' of github.com:pearlchen/yeoman.io into pearlchen-codelab-fixes-pearl

Conflicts:
	app/codelab/write-unit-tests.md
Merge branch 'pearlchen-codelab-fixes-pearl' into codelab-fixes
Merge pull request #246 from ahmadnassri/codelab-fixes

various fixing from following the codelab step by step [on Linux]