Improved unit testing adding Edge, Android and Iphone testing

[evilaliv3]

This commit:

• Add Edge, Android, Iphone to the tested platforms
• Diversify versions of testing for Chrome/Firefox including: an old one, the current stable, the ongoing beta
• Remove phantomjs; who cares of phantomjs anymore now that we have real testing?
• remove chai library; i added it initially for error but the project has never required this.
• Fix bug in https://github.com/dchest/scrypt-async-js/compare/master...evilaliv3:improved-unit-testing?expand=1#diff-67681eeab319685c5844c94363c9d7ddL30 were a null function was mapped to the 'fail' event, so that in case of a single failure all tests were going bad.
• update libraries to latests versions.

[dchest]

Thank you!