This is interesting work. We at Plasticity (YC S17) have open sourced something similar called Magnitude (https://github.com/plasticityai/magnitude) a few months ago for querying vector embeddings quickly with low memory usage using SQLite and a standard universal file format (.magnitude) between word2vec, fastText, and GloVe. We also added features for out-of-vocabulary lookups, bulk queries, concatenating embeddings from multiple models, etc. It may also be of interest to folks looking at this.
We also have a paper on Magnitude we will be presenting at EMNLP 2018 and ELMo support is coming soon!