Psrqpy

- Propagate errors on ecliptical coordinates to equatorial. See [90](https://github.com/mattpitkin/psrqpy/pull/90).
- Update build system. See [91](https://github.com/mattpitkin/psrqpy/pull/91).

- Move scraping of Galactic MSP catalogue into PSRQPy. See [88](https://github.com/mattpitkin/psrqpy/pull/88).

- Fix parsing of the galactic MSP table after changes to the upstream format. See [85](https://github.com/mattpitkin/psrqpy/pull/85).
- Remove explicit use of certain NumPy built-in types following their [deprecation](https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations). See [83](https://github.com/mattpitkin/psrqpy/pull/83).

- Add function to download and parse the galactic MSP table. See [80](https://github.com/mattpitkin/psrqpy/pull/80).
- Add functions to calculate derived gravitational wave parameters. See [79](https://github.com/mattpitkin/psrqpy/pull/79).

The major change for this release is that it no longer supports Python 2.7, and only supports Python versions
greater than 3.5.

- Add a function to download and parse the [globular cluster pulsar](http://www.naic.edu/~pfreire/GCpsr.html) table. See [#77](https://github.com/mattpitkin/psrqpy/pull/77).

- Allow `psrqpy` query to work using ATNF catalogue v1.64, which contains a position typo. See [74](https://github.com/mattpitkin/psrqpy/pull/74).
- More fixes to enable parsing of more references using NASA ADS and fixes changes that occurred with v1.64. See [70](https://github.com/mattpitkin/psrqpy/pull/70).