Replaced math.h with shogun include.

Pushed changes in other files with similar replacement of math.h.

Squash of previous 2 commits for replacing math.h with shogun include.

Changes in files as suggested in comments - removed unwanted includes lke math.h limits.h and SGIO include.

Squash of all commits including the suggested changes.
Merge pull request #2642 from srgnuclear/trial

Replacing math.h with shogun/mathematics/Math.h.
Merge pull request #2643 from sanuj/feature/SGVector_cleanup

Move arg_max/max_abs/arg_max_abs/arg_min from SGVector to CMath
do not predeclare and specialize template-class CEMBase
fixes for Mac OSX 10.10 Yosemite when using mp-gcc-4X
get rid of "-march=native"-flag
Merge pull request #2647 from shogun-toolbox/fix-osx-10.10

fixes for Mac OSX 10.10 (#2635)
Removed unwanted includes and shifted non shogun include to .cpp files.

Header includes glpk and cplex shifted back to .h

squash of 2 commits.
Merge pull request #2646 from srgnuclear/cincludes

Removed unwanted includes and shifted non shogun include to .cpp files.
Move mean/linspace from SGVector to CStatistics/CMath respectively