fix create/drop index functions

[kireev4art]

According to documentation I can do this:

try db.run(users.createIndex(email, ifNotExists: true))
// CREATE INDEX IF NOT EXISTS "index_users_on_email" ON "users" ("email")

and this:

try db.run(users.createIndex(email, ifNotExists: true))
// CREATE INDEX IF NOT EXISTS "index_users_on_email" ON "users" ("email")

But in fact:

import SQLite

let table = Table("table")
let field = Expression<Int64>("field")
table.createIndex(field, unique: true, ifNotExists: true)
// error: cannot convert value of type 'Expression<Int64>' to expected argument type '[Expressible]'
// table.createIndex(field, unique: true, ifNotExists: true)
table.dropIndex(field, ifExists: true)
// error: MyPlayground.playground:6:17: error: cannot convert value of type 'Expression<Int64>' to expected argument type '[Expressible]'
// table.dropIndex(field, ifExists: true)

So I removed:

public func createIndex(_ columns: Expressible...) -> String
public func dropIndex(_ columns: Expressible...) -> String

and changed:

public func createIndex(_ columns: [Expressible], unique: Bool = false, ifNotExists: Bool = false) -> String
public func dropIndex(_ columns: [Expressible], ifExists: Bool = false) -> String

to:

public func dropIndex(_ columns: Expressible..., ifExists: Bool = false) -> String
public func dropIndex(_ columns: Expressible..., ifExists: Bool = false) -> String

[kireev4art]

iOS version was updated to solve build error:

xcodebuild: error: Unable to find a destination matching the provided destination specifier:
{ platform:iOS Simulator, OS:10.3, name:iPhone 6s }
The requested device could not be found because no available devices matched the request.

But now there is a new problem that I don't really understand.
So, anyone, please look at travis logs.

[jberkel]

@kireev165 if you rebase against master it should work

[kireev4art]

@jberkel thanks. it seems that everything fine now

[jberkel]

applied: ac52569