Cleanup CMakeFiles

• There are several definitions in CMakeFiles which are not used any more (See also #390 (closed), #391 (closed)) Example:

add_definitions (-Drestrict=__restrict__)
add_definitions (-DNOCTAssert)
add_definitions (-DIPPL_LINUX)

• Fix indentation
• Fixes in coding style
• use add_definitions() and add_compile_options()
• commands are written in lower case
• write if commands like

if (FOO)
    ...
else ()
    ...
end ()