Ignore empty directories when snapshotting template directory

Ignore empty directories when snapshotting template directory.

Avoidance of deprecated APIs

Usage of deprecated APIs avoided for newer versions of Gradle.

Incremental task turned off when Rocker hot reload enabled

Incremental task functionality turned off when Rocker's hot reload feature is enabled.

Removal of empty output directories

Made RockerCompile task remove empty output directories.

Improved DSL

Changed DSL to declare version as part of the extension and to nest all configurations in a block.

Improved compatibility with task avoidance

Internal refactoring to improve compatibility with task avoidance.

Compatibility with task avoidance

Made RockerCompile task support configuration avoidance.

Usage of lazy properties

Internal refactoring to improve lazy properties usage.

Usage of InputChanges for incremental work action

Internal refactoring to get rid of deprecated APIs that will be removed in Gradle 7.

Compatibility with Gradle Configuration Cache

Made RockerCompile task compatible with the upcoming Gradle Configuration Cache. Support for versions of Gradle older than 6.0 is dropped.