Greater standardization of sizing terminology

BS3 commit 23ef8c0c209844dd8b92d2a5ac82daffa7bd2914
update line-height
add .btn-xs to .btn-group example

BS3 commi b9c572184f18a5c228dedd41e3b93b94c8d71b7b
JS docs: capitalize Bootstrap

BS3 commit eed4844fd2d12255c0e48acbf2b7132cefd6aaff
streamline $().dropdown('toggle') description

BS3 commit 899c147cd561a4fd8757cb76124036e5a73c5c92
trivial docs grammar improvements

BS3 commit b6390d298aa71e6dccb10e539097fbc7aaa45b8a
adjust description & give source for nested `.btn-group`s example

BS3 commit 509ffe110ecf78998a32e5603abedc79d526235d
components.html: rm disconnected sentence fragment

BS3 commit a84e07b27220eddb075d4df65fe24d26c722df7a
Greater standardization of sizing terminology

BS3 commit 23ef8c0c209844dd8b92d2a5ac82daffa7bd2914