several optimizations for search code

[Jamiras]

Improve both performance and memory footprint, particularly for consoles with larger amounts of exposed memory.

• break large ranges of matches into smaller groups when chunks of the original group are filtered out in a later group
• avoid comparing every item in a group if the entire group is unmodified
• use specialized functions for most common search types (i.e. "8-bit = Last Value")
• use bit vectors to keep track of matching items instead of an array of integers
• move several derived value calculations out of loops