fix(IE8): fix adjust height in IE8

use fallback to document.documentElement.clientHeight for height of window
docs(demo): add es5-shim to demo to test IE8
docs(demo): createNewOptions should use second half of existing options
docs(demo): add form surrounding select box
fix(options): set model value on change of options without making the form field dirty
chore(project): bump version to 0.3.3
docs(changelog): update changelog for 0.3.3
Merge branch 'hotfix/0.3.3'