Add bloom filter Reload method.
Made App Engine runtime compatible.
Remove embedded bloom.Filter mutex.

This prevents the caller from being able to accidentally lock or
unlock access to the filter internal state.

While here, remove several defers that do not gain us any readability,
and only hurt our performance.
Update test coverage report.
IMPORT PATH MODIFICATION CHANGESET
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Please use this changeset as the first one on top of the conformal codebase.
Note that if there are new imports, they need to be changed as part of this
changeset. In general, use "git rebase" on github.com/conformal's version
and apply this changeset first.