C_MountJournal changes

[Kharthus]

Some C_MountJournal functions were changed:

GetMountInfo -> GetMountInfoByID
GetMountInfoExtra -> GetMountInfoExtraByID
Summon -> SummonByID

The old functions took the mount index as an argument, the new functions use the mountID. They work regardless of filter settings in the mount journal.

A few new functions:

GetDisplayedMountInfo - New, takes an index like the original function, but only works on unfiltered mounts shown in the journal.
GetDisplayedMountInfoExtra - New, takes an index like the original function, but only works on unfiltered mounts shown in the journal.
GetMountIDs - New, returns a table of all the mount IDs.
GetNumDisplayedMounts - New, returns the count of all unfiltered mounts shown in the journal.

And new fanfare and search functions:

GetNumMountsNeedingFanfare - New
IsSourceChecked - New
NeedsFanfare - New
SetAllSourceFilters - New
SetSearch - New
SetSourceFilter - New