fix($state): use $browser.baseHref() when generating urls with .href()

If an angular app is placed in a subdirectory and a <base href="..." /> tag is used, ui-router should use the configured value when generating urls through $state.href(). Thanks to @mfield for the testing help!
feat(uiSref): add support for transition options

Allows optionally specifying options to be passed to $state.go via
attribute ui-sref-opts.
chore(travis): test against all angular versions
chore(files.js): Remove double entry

- Closes #876
Merge pull request #813 from roryf/ui-sref-options

feat(uiSref): add support for transition options
Merge pull request #528 from tgecho/basehref

Prepend the baseHref to $state.href() generated urls if it exists.
Automatically rewritten for npm.