Move unix_time(), id_cpy()/id_eq(), is_timeout()  to util.*

unix_time():
- returns local value for current epoch
- value is updated explicitly with unix_time_update() called at new_DHT()/doMessenger()/do_DHT()

is_timeout():
- uses the local value for current epoch

id_cpy()/id_eq() => id_copy()/id_equal():
- centralized duplicate definitions
- replaced (most) memcpy()/memcmp() of (*, *, CLIENT_ID_SIZE) with id_copy()/id_equal()
Merge remote-tracking branch 'upstream/master' into cleanup_unix_time_id_eq_cpy_is_timeout

Conflicts:
	toxcore/net_crypto.c
For security reasons, keep memcpy's and memcmp's in crypto functions.
All modules using unix_time should run unix_time_update()
Update time before running functions for recieved packets.
Clarified a comment.
Small changes to A/V
Merge pull request #633 from Martijnvdc/master

Small changes to A/V
Increased port range.
Merge branch 'master' of https://github.com/irungentoo/ProjectTox-Core
Cleaned up some code/fixed some warnings.

I'm sure nobody has any of the old save files anymore so I removed the
functions.
Public headers should not have any internal references
Merge pull request #634 from jin-eld/fix-public-headers

Public headers should not have any internal references
added AV_codec.h to public headers
renamed AV_codec to toxmedia
Merge pull request #635 from Martijnvdc/master

added AV_codec.h to public headers
Removed some now useless code.
Merge branch 'master' into harden

Also removed some old, useless loading code.
Testing requests are now sent.
Get node testing response packets are now handled.