Merge pull request #255 from hhromic/fix-254

Fix crash on errors in package-level `MustParse`

Merge pull request #243 from alexflint/handle-empty-placeholder

Handle explicit empty placeholders

Merge pull request #175 from alexflint/bracketing-positionals

Fix bracketing for non-required positionals in usage

Merge pull request #158 from alexflint/unexported-embedded

Recurse into unexported embedded structs

Merge pull request #153 from alexflint/test-empty-map

Fix case where an empty environment variable is parsed in a slice or map

Merge pull request #152 from alexflint/mappings-with-commas

Add an example of mappings with commas

Merge pull request #107 from alexflint/fix-issue-100

fix issue with duplicate fields in embedded structs

Merge pull request #91 from alexflint/defaults

Allow default values in struct tags

Merge pull request #82 from alexflint/subcommand-impl

Add support for subcommands

Merge pull request #70 from alexflint/create-go-mod

Migrate from Godep to go.mod