add support for showInputError() and close()
add support for showInputError() and close()

* closes #39
* expose SweetAlert.showInputError and SweetAlert.close functions (in both cases delegate them to `window.swal`, just like everything else does)

crowdcst/ngSweetAlert,oitozero/ngSweetAlert,esetnik/ngSweetAlert,xxxkonyi/ngSweetAlert,Elijax/ngSweetAlert,thescouser89/ngSweetAlert