Demuxer: emit PAT/PMT when seen

[tmm1]

This is a simple implementation of the fix discussed in #20

For now I am simply calling parseData, and only trying to flush early for PAT and PMT. In the future we could use a smarter/cheaper heuristic than a full parseData, and can also expand this to other types of PSI and PES.

Includes #21 and #23. I can rebase this whenever either of those are updated.

cc @barbashov @asticode

[coveralls]

Coverage increased (+0.6%) to 77.156% when pulling 96b3101 on tmm1:packet-pool-accumulator into c44c340 on asticode:master.

[asticode]

I like the idea of the accumulator (I remember I couldn't find a proper name for this logic but loves accumulator) but I feel some minor changes need to be done.

Also, those changes now have conflicts since I've started merging your PRs.

[tmm1]

I've updated the PR as requested, to:

• decouple Demuxer and packetPool
• merge master to fix conflicts
• improve hexToBytes to allow whitespace
• add TODO for partial parsing

I plan to remove the parseData in a follow-up PR.

I also had to turn programMap into a pointer so I could pass it down into the pool.

[tmm1]

Updated as requested.

[tmm1]

@asticode how does this look now?

[asticode]

Cheers