Merge pull request #84 from allmobilize/hzp

Hzp
update ScrollSpy doc & resolves #15;
update ScrollSpyNav
update collapse doc
remove `overflow-y: scroll` on html
add getScrollBarWidth util
resolves #75
using flexbox on button-group
update button.js;
update copyright info.
update Form & Input Group
Merge pull request #85 from allmobilize/codename-h

Codename h
Merge branch 'master' of https://github.com/allmobilize/amazeui into hzp

# By Minwe
# Via Codename H (2) and Minwe (1)
* 'master' of https://github.com/allmobilize/amazeui:
  update Form & Input Group
  update button.js; update copyright info.
  using flexbox on button-group
  resolves #75
  add getScrollBarWidth util
  remove `overflow-y: scroll` on html
  update collapse doc
  update ScrollSpyNav
  update ScrollSpy doc & resolves #15;