Qcache

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* Fix 10 & 11, minor statistics improvements

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* Fix 9, df overwritten by mistake

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* Compression using LZ4 or GZIP in requests and responses (3)
* Sub queries in "in" filter (7)
* Enum type based on Pandas category type (6)
* Support for stand in columns in queries (5)
* Additional metrics/statistics for complete request duration for stores and queries
* Update size estimates to do deep inspection of objects contained in dataframe. This should
be more accurate than the previous shallow inspection.
* Update Pandas to 0.19.1
* Update Tornado to 4.4.2

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* Fix packaging, the new qcache.qframe package was missing from the submitted package.

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* New filter engine based on Pandas rather than Numexpr. This enables new types of filters in the where
clause (see below). By default the old engine is still used but the new one can be enabled either
by default on server startup or on a per-query basis by setting the new 'X-QCache-filter-engine' header
to 'pandas'.
* New bitwise filters in the 'pandas' filter engine, 'all_bits' and 'any_bits'.
* New string filters, 'like' and 'ilike' which corresponds roughly to LIKE in SQL with the addition
of regex support. 'like' is case sensitive while 'ilike' is case insensitive.

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* Support TLS client certificate verification