Evaluate replacement for the PEAR/Net_DNS2 package

[cpliakas]

Having to require PEAR as a repository kills the performance of Composer package updates, and we are only using a small subset of the functionality. We should evaluate whether rolling our own thing would be a better options or whether we should continue to build on the package to be lock-step with the Acquia Cloud codebase.

[IlyaPokamestov]

@cpliakas could you please check #70, seems like build failed due to Scrutinizer internal error - not code related, in Travis all tests are passed.

[Zlender]

@cpliakas I think we should go ahead and switch to 1.4.1 net_dns2 separately from AC. If anything AC will start requiring customers to vendor dependencies and not rely on anything installed on servers by default.