Bug/mobile 14

* When logging in with PIN, a broken layout appears for a sec or so. fixes #2048
* A short delay after input the last PIN number. fixes #2042
* Back link as a button. fixes #2029
* Fixes of some unlogged layout issues.
* Swipe action to change pages (using bottom bar menu as reference). 
* Swipe action to show/hide sidebars. fixes #2010
not sure about this. I added "gray" the last commit :)

https://github.com/bitpay/copay/commit/4d040e600db7a4b79ab073b431abf657ca7e988c#diff-20965dc9ac022c0dc1f885a8cee10789L26