Parameter file in snapshot

Sorry @pdraper.... one more for you...

This is an implementation of #140. The parameter file key-value pairs are written to the snapshots. 
Changes are:
 - Write the parameters to the snapshot.
 - Reduce the size of the parameter file structure by changing the maximal amount of lines it can contain.
 - Added an error message for when this limit is reached.
 - Change the type `lock_type` to `swift_lock_type` in `lock.h`

This last change is because `lock_type` is used in some MPI function prototype and our "#define" interferes with some of the includes if you are not careful about ordering. That solves the problem by naming the lock type in a unique way.

Apologies for the rather large changelog that this generates for 5 actual lines of useful code... 

See merge request !173