Support android before 4.4 is broken in 4.0.7

[john-kolt]

I not found any information about android versions support. I was surprised when my application crahed on supported device. Version handlebars.java:4.0.6 works fine on androids before 4.4

I've updated from 4.0.6 to 4.0.7 and catch exception

    java.lang.NoClassDefFoundError: java.nio.charset.StandardCharsets
        at com.github.jknack.handlebars.helper.DefaultHelperRegistry.<init>(DefaultHelperRegistry.java:73)
        at com.github.jknack.handlebars.Handlebars.<init>(Handlebars.java:270)
        at com.github.jknack.handlebars.Handlebars.<init>(Handlebars.java:365)

StandardCharsets appeared in Android 4.4: https://developer.android.com/reference/java/nio/charset/StandardCharsets.html