Add Travis CI for Ubuntu 12.04 LTS

- Builds mastercored, mastercore-qt
- Runs Boost tests
- Runs applicable RPC tests
Replace global balance arrays with std::map

1. Doesn't cover full range of potential properties, can result in out-of-bounds violation
2. No need to reserve 100000 elements each
3. [] operator reads an element at position, if key exists, or inserts an element, if not