test(typeahead): corrects typos

Closes #1209
refactor(alert): clean-up unused variables
docs(README): add info about templates customization
docs(README): fix markup
fix(typeahead): prevent accidental form submission on ENTER
fix(datepicker): properly handle showWeeks config option

Closes #1132
docs(modal): fix double "a" typo

Closes #1214
fix(position): correct positioning for SVG elements

Bootstrap tooltips calculate the `width` and `height` of elements
using first getBoundingClientRect and fall back to `offsetWidth` and
`offsetHeight` if it is not available:

https://github.com/twbs/bootstrap/blob/master/js/tooltip.js#L297

This fixes a problem with tooltips/popovers on SVG elements in
Firefox: https://github.com/twbs/bootstrap/issues/5956

This change mimics that behavior.

Closes #1225