Add additional paths to path throughput test
Move lambda resolution to runtime

This has a very positive impact on precompiled output size, particularly for known-helpers cases, and little or no impact on the throughput numbers.
Rework lookup null protector logic

- Move the lookup null protection out of `nameLookup` and into that contexts that are aware of the needs for falsy vs. not displayed values.
- Optimize lookup for nested path operations

Fixes #731
Merge pull request #731 from wycats/path-lookup

Strange behavior for {{#foo}} {{bar}} {{/foo}} when foo is 0