Release candidate of version 8: hardness ratio and eff-area updated

Fix broken download interface from ASDC archive

ASDC (IT) implemented SSL to their HTTP data archive interface,
which has broken our (download) script.
I solved the issue by discarding ASDC (it was a shitty interface anyway)
and implementing the Leicester (UK) and NASA (USA) interfaces.
So now, those living in the Americas have a better/closer option to
retrieve data and Europeans will use the neighbours from North.

Merge pull request #1 from chbrandt/add-license-1

Create LICENSE

Merge branch 'master' of github.com:chbrandt/swift_deepsky

Update Swift Master Table to March/2018

Version 0.5: 'detect' labels, flux factor fixed

Fix confusion and flux rescaling inhomogeneous background

New master table, full-band at 3keV

Stable with exposure time for all events

Version 0.3