Do not run Gradle linter by default

It's rather slow, adding roughly five seconds to every "./gradlew"
invocation.  And the advice it gives might not even be reaching a
fixed point.  I like the idea of running the linter as part of CI
testing, but I now think it's overkill to impose on every developer
build.

build.gradle

@@ -80,7 +80,7 @@ subprojects {
 
 allprojects {
 	apply plugin: 'nebula.lint'
-	gradleLint.alwaysRun = true
+	gradleLint.alwaysRun = false
 	gradleLint {
 		rules = ['all-dependency']
 		excludedRules = [