Implement Summable, Invertible, Comparable for Duration

[dlkw]

Implements #713

Are tests in ceylon-sdk supposed to be running through? I could not get them to compile:

[ceylon-compile] /home/d3/prj/ceylon/ceylon-sdk/test-source/test/ceylon/http/server/module.ceylon:13: error: cannot find module artifact 'npm:@angular/platform-browser-dynamic-2.0.0(.car|.jar)'
[ceylon-compile]     import io.netty "4.0.2.Final";
[ceylon-compile]     ^
[ceylon-compile]   due to connection error: Unknown suffix in @angular/platform-browser-dynamic
[ceylon-compile]   	- dependency tree: 'test.ceylon.http.server/1.3.4-SNAPSHOT' -> 'io.netty/4.0.2.Final' -> '@angular/platform-browser-dynamic/2.0.0'

Signed-off-by: Dirk Lattermann [email protected]

[CPColin]

Is the actual parameter supposed to come first in assertEquals?

[dlkw]

See the test module docs, so, yes.

[CPColin]

See the test module docs, so, yes.

Some of your tests have the expected value first, instead of the actual value.