taxonomy: Samsung Galaxy S7, ecobee thermostat, more.

+ Add Samsung Galaxy S7, S7 Edge, Oneplus X, Xiaomi Redmi 3,
  ecobee thermostat, Panasonic TV, Sprint One M8.
+ Add alternate signatures for Xbox, Samsung Smart TV.
+ Add Windows OS DHCP signature (the first of many).
+ Reintroduce signatures previously gathered but suppressed
  according to the prior "1000 Fiber subscribers" rule.
  Amazon Fire Phone, several older iPhones, HTC One V and X,
  Nokia Lumia 920, Sony Xperia Z5.
+ Introduce the first Windows PC signature, one which is very
  common. PCs will never be so closely identified as mobile
  devices, but we can categorize them like "Windows 802.11n PC"
  and so forth.
+ Add tax_signature to .gitignore.

Change-Id: I91faa7e72c117ccf08f6c38ad765526a6e3e3af6
13 files changed