docs(contributing): fix typos

Closes #2566
fix(typeahead): replace ng-if with ng-show in matches popup

Fixes #2474
Fixes #2541
Fixes #2293
Closes #2535
Closes #2557
fix(modal): controllerAs not checked

This causes the controller to be added to the scope as a property "undefined"!

Closes #2564
docs(README): use svg instead of png to get better image quality

Closes #2629
fix(datepicker): memory leak fix for datepicker

Fixes #2658
Closes #2684