Build system updates

[OliverBenz]

General

• Rename tests project to physen.gtest
• Better output directory structure Output/[PlatformTarget]/[Configuration]/[lib | include | bin]

CMake

• Generate x86 and x64 solution if wanted

On Windows
CMake generated a .sln file on windows, so following changes would be nice to have

Different folders for projects in the solution:

• Physen: Contains physen and physen.gtest
• Examples: Contains rocket project and future examples
• Misc: Contains gtest, gtest_main, gmock etc

[OliverBenz]

All done except for x86 and x64 build.