Initial commit for the optimized GMP version

Changed bignum to GMP
Optimized algorithm
Added Share/hour and 5chain/h performance counters
Compiled 64bit version
Even more optimizations

More optimizations from mikaelh
Display Share value information
PrimorialMultiplier auto adjustment for optimal performance.
Added back the Total/Valid shares statistics
More parameters for tweaking

Add -d (SievePercentage) & -primes (SievePrimeLimit) command line
parameters that can be used for more tweaking
SievePercentage  ranges from 1 - 100, recommended is about 10 (default
is 8). It limits how many base primes are used to filter out candidate
multipliers in the sieve

The idea of SievePrimeLimit was taken from the latest official
jhPrimeMiner source. The default value is equal to MaxSieveSize which I
still recommend.
Changed the sampling time for the multiplier auto adjustment to 10 sec.
Fixed default sieveSize

the default sieveSize must be 1000000
Fixed crash + updated VS2010 solution

Fixed a crash that sometimes happened when the client was disconnected
from the pool
More merges