feat(nameProcessor): add support for param aliases
fix(typeProcessor): attach optional property to tag if type is optional
refact(tagDefs): update the tagDefs to work with the new tagParser
refact(MockTags): remove as we can use TagCollection instead
test(filter-ngdocs): use TagCollection rather than MockTags
style(tags.spec): remove unused variables
refact(tag-defs): ngdoc now adds to jsdoc tagdefs

Before, it was replacing the jsdoc tagdefs.
fix(tagParser): cope with tags that have no following whitespace
fix(tag-parser): add better error message
fix(typeProcessor): add better error message