remove useless display:inline-block. Remove commented out CSS. Remove more commented out CSS from forms. Update file input to remove height and line-height

BS3 commits 832fdf9a365689c9d50995b70a1f501c4555901b,
732e4196fb9dc76ce2250edcdc6c1b45bcbe5d2e,
51dfa21009459c98b8d98a63cfc3d2abe29f9017,
a63db4d2f91c056310fc9a24891dbd161672451b
Update file input to remove height and line-height

BS3 commit a63db4d2f91c056310fc9a24891dbd161672451b
Update forms example to show sequential form inputs for later testing. Update docs on responsive images and elaborate on IE8 support using Respond.js. Update file input to remove height and line-height

BS3 commits d651c01e10cd0f69529e5bcb20f5d1a4b6508c48,
df851b40d1accb1c6db44ac77a28c2e76273581b,
a63db4d2f91c056310fc9a24891dbd161672451b
Update file input to remove height and line-height

BS3 commit a63db4d2f91c056310fc9a24891dbd161672451b
refactor button-groups.less

BS3 commit e78ba0ff82e52221d33aaacd9f4bb526d04fd505
Update docs on responsive images and elaborate on IE8 support using Respond.js

BS3 commit df851b40d1accb1c6db44ac77a28c2e76273581b