Add SwiftLint (#49)

This change adds SwiftLint to the project. For now, the rules are tweaked
to match the current state of the code base — but will over time be changed
back to their defaults in several cases.

Some smaller changes (mostly related to code style) were applied to the
project to remove all warnings.

.swiftlint.yml

@@ -0,0 +1,7 @@
+disabled_rules:
+    - nesting
+line_length: 200
+function_body_length: 100
+type_body_length: 600
+file_length: 800
+cyclomatic_complexity: 15

Sources/Splash/Theming/Theme.swift

@@ -21,7 +21,10 @@ public struct Theme {
     /// What color to use for the text's highlighted tokens
     public var tokenColors: [TokenType: Color]
 
-    public init(font: Font, plainTextColor: Color, tokenColors: [TokenType : Color], backgroundColor: Color = Color(white: 0.12, alpha: 1)) {
+    public init(font: Font,
+                plainTextColor: Color,
+                tokenColors: [TokenType: Color],
+                backgroundColor: Color = Color(white: 0.12, alpha: 1)) {
         self.font = font
         self.plainTextColor = plainTextColor
         self.tokenColors = tokenColors

Tests/SplashTests/Tests/TokenTypeTests.swift

@@ -29,4 +29,3 @@ extension TokenTypeTests {
         ]
     }
 }
-