Compile sources with Java 1.8

Request for Lamda support.
The code without lambdas looks untidy and bulky.

I already do.

Lines 11 to 14 in e2e38b9

    
           compileOptions { 
        
           	sourceCompatibility JavaVersion.VERSION_1_8 
        
           	targetCompatibility JavaVersion.VERSION_1_8 
        
           }

The lambdas are still not used where possible:

	compileOptions {
	sourceCompatibility JavaVersion.VERSION_1_8
	targetCompatibility JavaVersion.VERSION_1_8
	}