general fixes and by_alt

this release has minor fixes to by_alt and other bugs:

• 8c692e2 - handle by_alt + float correctly (#113) (12 days ago)
• deeeee3 - Fix always falling back to non-bgzip reader (#109) (8 weeks ago)
• 54bcc00 - add go 1.11 (5 months ago)
• cc8048d - add release target to makefile (5 months ago)
• 5683246 - Add Makefile (#103) (5 months ago)
• 16701a1 - closes #99 (6 months ago)