Added project source files

This commits adds a FileTreeWalker module and a FileDigestCalculator.
Modified FileDigestCalculator to output triples instead of strings.
Added module to reorder elements in triples
Completed example showing how to find duplicate files
Fixed issue #77.

GenericXmlHandler now outputs empty strings instead of null if no id
attribute is found on record elements
Fixed #79

ObjectToLiteral should not output null as record id.
Fixed #74

TimerBase no longer fails if closed without processing any data.
Fixed #82

Created a utility class for time related helper functions and moved non
time logging specific code from TimerBase. Added test cases.
Durations of length zero caused an exception.
Added project source files

This commits adds a FileTreeWalker module and a FileDigestCalculator.
Modified FileDigestCalculator to output triples instead of strings.
Prepare for move to core package
Removed modules which are not yet moved to core from flux-commands.properties
Fixed Java 6/7 compatibility issue
Added modules from Xoff/metafacture-extra.

Modules:
	- FileDigestCalculator
	- TripleReorder

Merge remote-tracking branch 'mf-extra/move-to-core' into adding-modules-from-mf-core

Conflicts:
	src/main/resources/flux-commands.properties
Added support for user-defined increments for the range-collector. Fixes
issue #90.
Ignore name/date line in when checking license header
Tidied up SimpleXmlWriter to prepare for refactoring
Changed SimpleXmlWriter to call process only once per record.
Added a filter for triples

The filter matches subject, predicate and object against regular
expressions. Triples are only passed on (or filtered) if at least one of
the regexp matches.