Added max.snapshot.size parameter to ddg.init and ddg.run.
Updated expected results and documentation.
Merge branch 'master' of https://github.com/blernermhc/RDataTracker.git

Conflicts:
	examples/depends.r
Updated version number
Add ddg.function and modify ddg.procedure
Merge branch 'master' of https://github.com/blernermhc/RDataTracker
Add ddg.function and modify ddg.procedure
Conflicts:
	R/RDataTracker.R
	examples/checkpointTest/expected_checkpointFileTest.out
	examples/checkpointTest/source_expected_checkpointFileTest.out
	examples/consoleSource/expected_consoleSource_ddg.txt
	examples/consoleSource/source_expected_consoleSource_ddg.txt
Restored env parameter to .ddg.create.data.node.for.possible.writes.

Changed calls to .ddg.link.function.returns to pass in the string
version of the command, not the parsed command.
Changed code to avoid duplicate node creation when executing ddg.eval
when running a script with ddg.source.
Fixed problem with not finding return statements due to differences in
spacing between original text and deparsed value stored in the returns
table.

Fixed problem with duplicate start, finish and data nodes when
ddg.source is used, calls ddg.eval, which in turn calls a function that
is annotated with ddg.function.
Removed .ddg.in.ddg.eval variable since it is not needed to solve the
ddg.source -- ddg.eval problem.
Updated version number, cleaned up library, added Eval2Test to test
suite.
Eliminated creation of extra node when ddg.eval is used from the
console.
Eliminated empty console start-finish pairs
Cleaned up the code.
Updated version number
Changed ddg.return to create the function node for the function that is
returning if it does not already exist.
Documentation updated in scripts and help messages
Merge branch 'master' of https://github.com/blernermhc/RDataTracker
Update documentation in scripts and help files.

Conflicts:
	DESCRIPTION
	R/RDataTracker.R
Passing 0 for max.snapshot.size to ddg.init or ddg.run now results in no
snapshots at all.  Instead data nodes with no value are created.
Merge branch 'master' of https://github.com/blernermhc/RDataTracker.git

Conflicts:
	DESCRIPTION
	R/RDataTracker.R