The marks are parsed from the metadata definition, then merged from all
threads and a new channel for each mark type is created. The channel
type is specified using a flag when calling ovni_mark_type(), so the
channels is set to single or stack. For now, only ovni_mark_push() and
ovni_mark_pop() are implemented.
In order to allow easy debugging of some programs and runtimes, it is
often neccessary to add extra information in the timeline views. The
modification of the emulator to accomodate those temporal events is time
consuming and requires knowlegde of the emulator internals.
To improve the situation, a new set of functions are added to libovni
which allow users to define their own views. Up to 100 types of events
can be declared, where each type can have an unlimited number ov values
with an optional label attached.
