Depot path filter

Changes can be filtered to not trigger a build; if all the files within a change match the specified path, the build is filtered.

For example, with a Filter of " `//depot/main/tests` ":

Case A (change will be filtered):

Files:

- `//depot/main/tests/index.xml`
- `//depot/main/tests/001/test.xml`
- `//depot/main/tests/002/test.xml`

Case B (change will not be filtered, as build.xml is outside of the filter):

Files:

- `//depot/main/src/build.xml`
- `//depot/main/tests/004/test.xml`
- `//depot/main/tests/005/test.xml`