removed externeous binding
fixed: default select value
added: basic validation
added: disabling button on invalid
prettier
Merge branch 'step4' into step4.1
Merge branch 'step4.1' into step5
Merge branch 'step5' into step5.1
removed: redundant field
Merge branch 'step5.1' into step6

with error with the clear
removed: clear
demonstrate different bindings
added: ng-show
nicer
Merge branch 'step6' into step6.1
Merge branch 'step6.1' into step6.2

Conflicts:
	index.html
ngshow
Merge branch 'step6.1' into step6.2