Switched to markdown code blocks
Merge pull request #47 from Mause/patch-1

Switched to markdown code blocks
Header moving part 2

Somehow the last commit wasn't complete. This is now the complete
commit.
Merge branch 'develop' of https://github.com/adam4813/Sigma into develop
SOIL include fix

SOIL/SOIL.h ==> SOIL.h

(see FindSOIL.cmake - it searches for and includes SOIL.h with FIND_PATH)
Gtest tests added as a dependent subproject

SigmaTests is built automatically with cmake after the main project is built
Fixed relative includes to use include/ directory