Added two kernels to existing SVM framework
Histogram intersection kernel (accessible by using SVM::INTER in CV namespace as kernel_type)
Exponetial chi2 kernel (accessible by using SVM::CHI2 in CV namespace as kernel_type)

Formulars:
Exp-CHI2
k(x,y) = exp(-gamma * CHI2(x,y))
CHI2(x,y) = 1- 2* SUM_i[(xi-yi)²/(xi+yi)]

Intersec
k(x,y) = SUM_i[min(xi,yi)]
Changed line 1266 in svm.cpp to allow the new kernels to be used
Corrected a mistake in CHI2 kernel in line 354 and line 362 svm.cpp
Added new kernels to documentation
Merge pull request #490 from mschoeler:master