Products.zcatalog

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- Fixed addition of two LazyCat's if any of them was already flattened.

- Extend BooleanIndex by making the indexed value variable instead of
hardcoding it to `True`. The indexed value will determine the smaller set
automatically and choose its best value. An inline switch is done once the
indexed value set grows larger than 60% of the total length. 60% was chosen
to avoid constant switching for indexes that have an almost equal
distribution of `True/False`.

- Substitute catalog entry in UUIDIndex error message.

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- Optimize `Catalog.updateMetadata` avoiding a `self.uids` lookup and removing
inline migration code for converting `self.data` from non-IOBTree types.

- In the path index, don't update data if the value hasn't changed.

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- Optimize DateRangeIndex for better conflict resolution handling. It always
starts out with storing an IITreeSet of the value instead of special casing
storing an int for a single value. The `single value as int` optimization
should be provided via a separate API to be called periodically outside the
context of a normal request.

- Replaced `weightedIntersection` and `weightedUnion` calls with their
non-weighted version, as we didn't pass in weights.

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- Fix possible TypeError in `sortResults` method if only b_start but not b_size
has been provided.

- Prevent the new UUIDIndex from acquiring attributes via Acquisition.

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- Handle `TypeErrors` in the KeywordIndex if an indexed attribute is a method
with required arguments.

- Added reporting of the intersection time of each index' result with the
result set of the other indexes and consider this time to be part of each
index time for prioritizing the index.

- Removed tracking of result length from the query plan. The calculation of the
length of an intermediate index result can itself be expensive.

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- Added a floor and ceiling value to the date range index. Values outside the
specified range will be interpreted the same way as passing `None`, i.e.
`since the beginning of time` and `until the end of it`. This allows the
index to apply its optimizations, while objects with values outside this
range can still be stored in a normal date index, which omits explicitly
passed in `None` values.