Added failing unit test.

Test demonstrates that, unless time moves in exact 10ms steps, the
timer store can lose track of which bucket a timer is in, breaking
update functionality.
Force time to move in 10ms steps
Update cpp-common module
Merge pull request #26 from Metaswitch/module_update

[No reviewer] Update cpp-common module
Better comments to explain the bucket finding algorithm
UT for time moving to near one second boundaries
Merge pull request #27 from Metaswitch/fix-use-after-delete

Reviewer Ellie - Fix use after delete
Update cpp-common module
Merge pull request #28 from Metaswitch/mod_update

[No reviewer] Update cpp-common module
Allow chronos to write out core files
Merge pull request #31 from Metaswitch/issue29

[Reviewer: Andy][From: Alex] Allow chronos to write core files.
Update cpp-common for multiple diameter connections support
Merge pull request #33 from Metaswitch/sto639

Update cpp-common for multiple diameter connections support