Added support for gzip compressed FITS files.
Added test for gzipped FITS files
Updated test directory entry counts in testcases
simplified the time conversion from utc to tai
Fix mapcube.plot()
changed tabs by spaces in documentation of `parse_time`
and added blank lines before each section.
Made test file smaller
Added .fit to possible fits extensions
Added tests for .fit.gz and .fts.gz
Merge pull request #1161 from Cadair/map_cube_fixes

[BugFix]: Fix mapcube.plot()
Merge pull request #1160 from dpshelio/jsoctime

[Review]: simplified the time conversion from utc to tai
Updated CHANGELOG
Only do regex match after gzip check has failed.
Used format instead of the old % syntax
Merge pull request #1135 from rubendv/gzip

[Review]: Added support for gzip compressed FITS files.