make test scripts fail when a test fails
added a new kernel SSKStringKernel which implements the subsequence kernel (by lodhi et. al.). Also added to the modular interface
Added log_det method in CStatistics class
indentation fixed in Statistics.h
Fixed the previous messy commits
Unit test for log_det added. log_det updated.
Fixed doxygen info in log_det
Modified the unit test for log_det
Fixed indentation in Statistics.h
Merge pull request #956 from lambday/master

Added log_det method in CStatistics for Dense matrices
A splat for KRR test
move normalizer assignment to init() to avoid code duplication
normalize LA kernel to have norm 1 on the diagonal
add missing include to fix compile error
normalize diagonal to one for LIK by default
include normalizer after kernel header file to fix compile error
likely fix oligokernel bug
String kernel fixes

- add reasonable sqrtdiag normalizer to LI kernel
- add convenience constructor to the oligo kernel
- add slow compute function back to oligo kernel
- use SGVector instead of ptr & len
Bugfix for SLIK kernel

- remove left over init code in compute function of SLIK kernel
- this init code caused an unstable pyramid array, making
the kernel fail when #threads > 1
fix data generator for kernel integration tests