Moved code around so that it matches the default implementation of the
assets pipeline.
i.e. Created a LessProcessor and set that against the AssetFile

This is useful as other processors can be inserted to act before less
compilation.
Moved statics to the correct compiler implementation.
Renamed to AbstractLessCompilerImpl
Updated the javascript to point to the correct classes that declare the
static methods.
Updated thread local location.
Wrong type declared.
Renamed Abstract class.
Upped less4j version to 1.8.2

Fixes an error java.lang.NoSuchFieldError: EOF_TOKEN thrown for some
less files.
Merge pull request #15 from k-int/rework-into-standard-processor

Refactor