Travis/repopoulation crossover fix

[travisdesell]

Updated the repopulation methods so that:

• intra-island crossover is done within an island if it is full (even if other islands are not full or repopulating).
• inter-island crossover is done if the current island and any other island are full (as opposed to requiring all islands being full).
• adds exporting genomes with required information to JSON for visualization of search progress
• genomes now track the IDs of their parent(s)

[jkarns275]

LGTM

[jkarns275]

Doesn't really matter but I would avoid duplicate allocation with:

    assert(n_parent_ids > 0);
    parent_ids.assign(n_parent_ids, 0);
    bin_istream.read((char *) &parent_ids[0], sizeof(int32_t) * n_parent_ids);