Add conversions for Julian dates

v0.5.1

Fix DateFormat link (#96)

Drop Julia 0.4/0.5 and tzdata 2017c

Merge pull request #94 from JuliaTime/cv/compat

Compatibility changes for latest Julia 0.7

Fixes for hash, pre-compilation, compilecache detection

• Implement hash for ZonedDateTime
• Correct logic mistake when detecting if Julia was run with --compilecache=yes
• Enable pre-compilation
• Update documentation to prefer usage of tz string macro
• Fix Markdown rendering of * in FAQ when view in GitHub
• Support parsing of FixedTimeZone information from TZ environment variable to support Travis CI changes
• Disable Coverage in AppVeyor in Julia 0.4 as master version of Coverage.jl does not support Julia 0.4
• Fix incorrect usage of SystemError

Fixes isless redefinition warning

v0.4.1

Use official Coverage.jl support for Appveyor