Framework should be able to insert timing calls

[gold2718]

capgen could take an option to insert host-model specific timing calls which would then be inserted in the generated code. Some initial thoughts and questions:

• The option would have to specify start and stop functions along with a module.
• The details could be included in the type = host ccpp-data-table at which point the capgen option only needs to be a boolean.
• The timers used by CESM allow nesting meaning that calls could be inserted at both the group level and at the individual scheme-call level. @climbfuji, @davegill, is this true of timers used in your models?
• The timers used by CESM take a single character string argument which is how entry and exit are marked. @climbfuji, @davegill, what is the interface to timers used in your models?