ui: Use pointers for methods

Signed-off-by: Fam Zheng <famz@redhat.com>
README: Update TODO and description

Signed-off-by: Fam Zheng <famz@redhat.com>
ui: Colors and UI loop

Signed-off-by: Fam Zheng <famz@redhat.com>
locale: Add locale.go for SetLocale(3)

Signed-off-by: Fam Zheng <famz@redhat.com>
ui: Display UTF-8 subject

Signed-off-by: Fam Zheng <famz@redhat.com>