Ensure swiftTypeWrapper only wraps types in its own matchgroup

Enum members, numbers, other literals like string will be highlighted
separately as part of their own matchgroup.

The result is that this:

fixes #93
fixes #90
fixes #89

Author: Akshay Hegde

example/example.swift

@@ -360,3 +360,12 @@ self.init(className: "Item", dictionary: [
     "summary": item.summary])
 
 XCAssertEqual(variables as NSDictionary, expectedVariables as NSDictionary, "\(template)")
+
+NSWorkspace.sharedWorkspace().notificationCenter.addObserver(
+    self, selector: #selector(self.activeApplicationChanged(_:)),
+    name: NSWorkspaceDidActivateApplicationNotification, object: nil
+)
+
+public func find(closure: @noescape Element throws -> Bool) rethrows -> Element? {
+
+}

syntax/swift.vim

@@ -220,7 +220,7 @@ syntax keyword swiftDebugIdentifier
 
 syntax keyword swiftLineDirective #setline
 
-syntax region swiftTypeWrapper start="\v:\s*" skip="\s*,\s*$*\s*" end="$\|/"me=e-1 contains=ALLBUT,swiftInterpolatedWrapper transparent
+syntax region swiftTypeWrapper start=":\s*\(\.\)\@!\<\u" skip="\s*,\s*$*\s*" end="$\|/"me=e-1 contains=ALLBUT,swiftInterpolatedWrapper transparent
 syntax region swiftTypeCastWrapper start="\(as\|is\)\(!\|?\)\=\s\+" end="\v(\s|$|\{)" contains=swiftType,swiftCastKeyword keepend transparent oneline
 syntax region swiftGenericsWrapper start="\v\<" end="\v\>" contains=swiftType transparent oneline
 syntax region swiftLiteralWrapper start="\v\=\s*" skip="\v[^\[\]]\(\)" end="\v(\[\]|\(\))" contains=ALL transparent oneline