added CoverageFilter and test
wired CoverageFilter into plugin and added options to configure custome exclusion filter regexs
changed to use a regex against the source file name
changed name of control variable to ...  scct.excluded.paths.regex

 example
	<configuration>
					<systemPropertyVariables>
						<scct.debug>false</scct.debug>
						<scct.project.name>${project.name}</scct.project.name>
						<scct.coverage.file>${project.build.outputDirectory}/coverage.data</scct.coverage.file>
						<scct.report.dir>${project.build.directory}/coverage-report</scct.report.dir>
						<scct.source.dir>${project.build.sourceDirectory}</scct.source.dir>
						<scct.excluded.paths.regex>src/main/scala/.*Excluded,other/excluded/path/regex</scct.excluded.paths.regex>
					</systemPropertyVariables>
				</configuration>
added new file accidentally missed on last commit
merged from head
corrected typo in variable name
Merge pull request #31 from Johnlon/master

Added feature to exclude files from coverage analysis