Created initialization function for Core-specific configuration variables

Similar to commit 3268e72f51b22e0780ef0f74f90d7bb9f5d610a1, this commit
creates an initialization function for Core-specific configuration
variables. As with the aforementioned commit, depending on the code
execution path, there was previously the possibility of attempting to
free a pointer variable whose value was pointing to something in the
data segment. This commit fixes that.

Additionally, previously the variables were being initialized in two
places: when they were declared and in the reset_variables() function.
In several cases they were initialized differently and that difference
has been maintained. Whether they should be initialized differently
should still be determined. For any variables that were being initialzed
the same in both places, they are now only initialized once.
Scheduling: Added macros for min and max nugde values

Nudge values are used to move service checks ahead in time when the
maximum number of parallel service checks has been exceeded. This
commit creates macros for the min and max nudge values and thus rids
the world of two more undocumented numeric constants.
Fix bug in check_window() macros

This commit corrects the logic in the check_window() macro so that
the macro returns the retry interval when the object (host or service)
is in a non-OK soft state and the check interval otherwise. Previously
it was returning the retry interval only when the object was in a soft
OK state meaning that checks for objects in OK states were happening
more often than necessary and checks for objects in non-OK states
weren't happening as often as they should.
Tests: test_events once again passes all tests
Tests: test_downtime once again passes all tests
Update .gitignores to clean up git status output