Memory optimizations

[Mario Zechner]

Use dev tools and memory snapshots to cut down on required memory.

• Don't calculate full url in processItems(). Construct on demand in items-list.js during item rendering. 166 - 159mb
• De-duplicate strings in ids, names, dates, etc. 159mb - 145mb
• Use getters instead of precalculated values for fields used in alasql queries. 145mb - 92mb