Flexible tag names

[icmurray]

Allowing more flexible tag names:

• allowing spaces
• allow capital letters (search is case in-sensitive)
• allow all punctuation except for commas and double-quotes '"'
• allow unicode
• commas delimit tag names in the package create/edit form

Effects:

• package creation/edit form.
• /tag/{tagname} uri
• search action
• api controller (search/package-create/edit)
• web controller (search/package-create/edit)
• search api documentation
• autocomplete for tag names

[icmurray]

Added the restriction of not allowing the double quote character, '"', as well as commas as this simplifies any use of quoting multiple words to mean a single tag name.

For example, this simplifies the use of quotes in identifying tags in internal markdown links:

tag:"multiple word tag name"

A possible solution is to allowing escaping, such as:

tag:"something about \"Ian\""

But I think the compromise is a better solution than allowing the escaping as it's simpler, and this may crop up elsewhere.

[icmurray]

The allowable characters in a tagname has changed to "unicode alphanmeric plus simple punctuation". This means:

• alphanumeric (inc. foreign characters)
• [ .-_]

The completed feature is in the ​feature-1453-flexible-tag-names branch.

Awaiting a code review.