Restore some fling parameters

one of the bugs I'm flailing on that are nagging at me is related to skippiness when flinging at high velocity

it's either related to constants in ViewConfiguration or(/and) animation stuff that could be handled more efficiently

MAXIMUM_FLING_VELOCITY:
stock     8000
ours was 15000

px = dp * (dpi / 160)
gsf = 430 dpi
15000 dp/s * (430 / 160) = 40312.5 px/s
on a 1080x1920 device, that's 21 screen-heights per second fling
I don't think we need to worry about flings being initiated with a 21 screen-height/second
so, returning MAXIMUM_FLING_VELOCITY to 8000 (stock val)

SCROLL_FRICTION:
stock    0.011
ours was 0.015
DADDY LIKES A SMOOTH RIDE, but this seems like it could lead to scroll inertia eventually
outrunning the scrolling cache. To prevent that, let's try the stock value.

Change-Id: I098399cf6f32661020d947eb27742bfda69161dd
Identicons: Add identicons to ChaOS Lab [1/3]

When enabled, new contacts will be assigned a unique
5x5 identicon as the contact photo instead of the boring
default one.

PS2:
Make Identicon an abstract class so we can use it to
create different types of identicons.  For starters
we'll use the github style in GithubIdenticon.  This
opens up the door to other types.

PS3:
Season with some salt.

PS4:
Use PNG format and tag it using an iTXt chunk before the
IEND to tag it with "identicon_marker" indicating it is
an identicon.  We can use this to identify if a photo is
an identicon and if so do what we want with it, like
removing identicons.

PS5:
We'll stick with JPG format and add a comment block to
the end.

PS6:
Better...stronger...faster.

PS7:
Add the dot matrix identicon

PS8:
Rename PolkaDotsIdenticon to DotMatrixIdenticon

PS9:
Clean up for release and add proper ChaOS Lab annotations.

Change-Id: I95fdca30686a2993ba5c2a9024a3cf5935b5d360