Stratum servers can now be named.
The names will be used throughout the display in the program, when not set "Pool 1" will
simply be used instead. The names are not exposed through API yet, it's on my TODO list.

Use "poolname" like this:

	{
		"poolname" : "Example pool",
		"url" : "stratum+tcp://example.com:8080",
		"user" : "y",
		"pass" : "x"
	},

Conflicts:
	sgminer.c
	util.c
EXPERIMENTAL: A new way of setting intensity; introducing xintensity!
All of this is credited to ArGee of RGMiner, he did the initial ground work for this setting.

This new setting allows for a much finer grained intensity setting and also opens up for dual gpu threads on devices not previously able to. Note: make sure to use lower thread-concurrency values when you increase cpu threads.

Intensity is currently used to spawn GPU threads as a simple 2^value setting.
  I:13 =    8192 threads
  I:15 =   32768 threads
  I:17 =  131072 threads
  I:18 =  262144 threads
  I:19 =  524288 threads
  I:20 = 1048576 threads
Notice how the higher settings increase thread count tremendously.

Now enter the xintensity setting (Yes, I am a genius with my naming convention!).
It is simply a shader multiplier, obviously based on the amount of shaders you got on a card, this should allow the same value to scale with different card models.
   6970 with 1536 shaders: xI:64 = 98304 threads
R9 280X with 2048 shaders: xI:64 = 131072 threads
 R9 290 with 2560 shaders: xI:64 = 180224 threads
R9 290X with 2816 shaders: xI:64 = 163840 threads

   6970 with 1536 shaders: xI:300 = 460800 threads
R9 280X with 2048 shaders: xI:300 = 614400 threads
 R9 290 with 2560 shaders: xI:300 = 768000 threads
R9 290X with 2816 shaders: xI:300 = 844800 threads

It's now much easier to control thread intensity and it potentially allows for a uniform way of setting the intensity on your system. I'm very interested in constructive feedback, as I do not have access to a lot of different card models.

This change has been tested on 6970, R9 290, R9 290X - all with equal or a little better speeds than regular intensity setting after a little tuning, but your mileage may vary. Don't fret it, if this doesn't work for you, the regular intensity setting is still available.

Conflicts:
	driver-opencl.c
	sgminer.c
Use lround instead of llround, since it has better compatibility with older MingW and Cygwin versions
misc: Add Luke-jr back to AUTHORS.md and reorder a bit.
core: Accidentally left a part of a previously non-merged commit (thread display).

IMO threads don't change dynamically, so they shouldn't be displayed
in the main window, but in "GPU settings" menu instead.
core: initial implementation of user-settable xintensity. Has a bug.

Changing `intensity` and to it from `xintensity` works fine.

Changing `xintensity` sometimes fails to enqueue kernel.

For example, starting with --xintensity=128 (on a 5850) and
then changing to 64, 42, or 100 is reliable. However, changing to 127 is
not, and produces

    [04:13:01] Error -54: Enqueueing kernel onto command queue. (clEnqueueNDRangeKernel)
    [04:13:01] GPU 0 failure, disabling!

Manually enabling the disabled GPU is successful, but the GPU no longer
submits shares.

This might be a hardware limitation.
core: don't use magic numbers to set xintensity.