Dynamic mask support to InputMask

[jogelin]

**I'm submitting a **

[X ] bug report

Plunkr Case (Bug Reports)
http://plnkr.co/edit/uZdjjvGH3IhqYElGJvnm?p=preview

Current behavior

1. Set initial mask to 10 digits: "9999999999" -> the input correctly displayed: "__________"
2. Change the mask, by example to 5 digits: "99999" -> the input doesn't change, it still displayed: "_____"

Expected behavior
I expect to be able to change the mask of an input mask dynamically

Minimal reproduction of the problem with instructions

1. Set initial mask to 10 digits: "9999999999" -> the input correctly displayed: "__________"
2. Change the mask, by example to 5 digits: "99999" -> the input doesn't change, it still displayed: "_____"

• Angular version: 4.x.x
• PrimeNG version: 4.0.0-RC4