Materials index and new Encyclopedia API
Added separate ES index for materials, implemented new much faster Encyclopedia API based on that index, added CLI command for (re)-indexing materials, updated the Phonopy parser to output calculation references, improved Enc API documentation, added option to search band gap ranges in Enc GUI, added option to restrict searches to individual calculations in the Enc GUI (this sort of replaces the obsolete "complex search" options which were not even working in the old version..)
This branch is currently running on the beta deployment and can be tested there.