Timescaledb: 0.8.0 Release

High-level changes * TimescaleDB now builds and runs on Windows! Now in addition to using Docker, users can choose to build the extension from source and install on 64-bit Windows * Update functions add_dimension and set_chunk_time_interval to take INTERVAL types * Improved tablespace management including detaching tablespaces from hypertables and looking up tablespaces associated with a hypertable * Reduced memory usage for INSERTs with out-of-order data * Fix inserts on 32-bit architectures, in particular ARM * Other correctness improvements including preventing attachment of PG10 partitions to hypertables, improved handling of space dimensions with one partition, and correctly working with pg_upgrade * Test and build improvements making those both more robust and easier to do

Notable commits * [26971d2] Make tablespace_show function return Name instead of CString * [2fe447b] Make TimescaleDB work with pg_upgrade * [90c7a6f] Fix logic for one space partition * [6cfdd79] Prevent native partitioning attachment of hypertables * [438d79d] Fix trigger relcache handling for COPY * [cc1ad95] Reduce memory usage for out-of-order inserts * [a0f62c5] Improve bootstrap script's robustness * [00a096f] Modify tests to make more platform agnostic * [0e76b5f] Do not add tablespaces to hypertable objects * [176b75e] Add command to show tablespaces attached to a hypertable * [6e92383] Add function to detach tablespaces from hypertables * [e593876] Refactor tablespace handling * [c4a46ac] Add hypertable cache lookup on ID/pkey * [f38a578] Fix handling of long constraint names * [20c9b28] Unconditionally add pg_config --includedir to src build * [12dff61] Fixes insert for 32bit architecture * [e44e47e] Update add_dimension to take INTERVAL times * [0763e62] Update set_chunk_time_interval to take INTERVAL times * [87c4b4f] Fix test generator to work for PG 10.1 * [51854ac] Fix error message to reflect that drop_chunks can take a DATE interval * [66396fb] Add build support for Windows * [e1a0e81] Refactor and fix cache invalidation

Thanks * @oldgreen for reporting an issue where COPY was warning of relcache reference leaks * @campeterson for pointing out some documentation typos * @jwdeitch for the PR to prevent attaching PG10 partitions to hypertables * @vjpr and @sztanpet for reporting bugs and suggesting improvements to the bootstrap script