Installation scripts for daemon mode on Ubuntu using Upstart

This work is based upon upstream work in bitcoin core on the master branch and in some PRs.
The "Cherry Pick" commit is here: https://github.com/msgilligan/mastercore/commit/55a97b93223919171195fb11c11281c9cdb0be3e

All files (both the "cherry pick" files and the ones that I've added are in the `contrib` subdirectory.


Hey @dexX7, why did you raise nMinRelayTxFee from 1000 to 1001? (I'm working on submitting a new PR and want to incorporate your suggestions and understand the issues better.) It seems to me that the best solution is to comment this line out, though.

This `bitcoin.conf` file should be the default for Master Core and should be secure and have the best general purpose settings for `bitcoind` running in background mode. I'm happy to take any suggestions -- or complete configuration files -- for what its contents should be.

(Note: I created this `bitcoin.conf` file by copying `contrib/debian/examples/bitcoin.conf` and adding `txindex=1` as required by Master Core.)