v0.4.2

AstroLib v0.4.2

Diff since v0.4.1

Closed issues:

• Adstring outputs wrong string with negative zero (#57)
• Could not find file NP.xy (#69)
• Why does sunpos accept both scalars AND vectors? (#72)
• Type of sunpos is too restrictive for use with ForwardDiff (#73)

Merged pull requests:

• Fix Saturn mass. (#71) (@TobiasHeinicke)
• Fix adstring method (#74) (@Aman-Pandey-afk)
• Type Relaxation on sunpos (#76) (@Aman-Pandey-afk)
• Remove Coveralls.io badge from README (#77) (@mortenpi)
• Fix Mars mass and period (#78) (@jjor2)